The Night Rules at Blackthorn Service Station

I pulled into the car park at Blackthorn Service Station fifteen minutes before my shift and watched a dark green hatchback come to rest diagonally across two marked bays.

The new bloke.

Management had told me the day before that I would be training someone that night. The driver's door opened and a young man climbed out, his hair untidy and his uniform shirt creased. He had his mobile in one hand and a large can of strong iced coffee in the other.

As a single mother of two children, I could not afford to lose this job. Blackthorn paid nearly twice the usual local rate for working in a forecourt shop, which meant I could put food on the table and even save a little each month. There was a reason for the exceptional pay, of course, but it was not the sort of thing anyone mentioned in a job advert.

The new employee approached with an easy smile and held out his hand as I got out of my car.

"Callum Price," he said. "You must be Sarah Mercer."

I nodded, shook his hand briefly and headed towards the roadside shop.

"Just call me Sarah. Let's get inside and I'll show you round."

The fluorescent tubes buzzed overhead as I unlocked the front doors. The duty manager would not arrive until much later, which gave me plenty of time to cover the basics with Callum.

And by basics, I meant the rules. The very important rules that kept us alive.

"So," Callum said as he followed me inside, "Graham said you've been here a while."

"Three years," I replied, walking behind the counter and putting my handbag in the locked staff drawer. "Which means I've outlasted nine other employees who failed to take this job seriously over the past four years."

Callum laughed, plainly assuming I was joking.

I was not.

"Right. Before we get to till training, there are some rules specific to this station that you need to know." I watched his face carefully. "Rule 1: never work alone. No matter what happens. If someone rings in sick, you call me or another employee before you begin a shift by yourself."

Callum nodded as he straightened his name badge.

"Fair enough. Safety in numbers and all that."

"This isn't about preventing robberies," I said firmly. "Two years ago, a man called Nathan Cole decided to cover an overnight shift alone when his partner rang in sick. The CCTV showed him working normally until a security incident at 02:23. He looked up at something beyond the camera, walked into the stockroom and never came out."

Callum's smile diminished.

"What? You mean he stole something and did a runner through the back?"

I shook my head. "The staff exit was locked from the inside. All his belongings were here. His car was still in the car park. He simply vanished."

"That's..." Callum began, then shrugged. "A strange coincidence, I suppose."

I could already tell that training him was going to be difficult. Some people refused to believe until they saw something for themselves. Even then, they often tried to explain it away. I had seen the same reaction from other new employees.

"Let me show you the layout," I said, changing tactics.

I could return to the rules as relevant situations arose during the shift.

I walked Callum through the aisles, showing him where the stock belonged, how to check use-by dates and how to rotate products properly. He seemed intelligent enough. He asked sensible questions about stock and picked things up quickly.

When we reached the refrigerated section, I handed him a box of canned drinks to put away.

"Why is the pay so good here?" he asked as he arranged the cans in the chiller. "Most forecourt shops pay minimum wage."

"The unusual hours," I lied.

It was not entirely untrue.

"And the special circumstances."

"Special circumstances?"

Before I could answer, a loud scratching came from the customer toilet. It sounded like fingernails being dragged slowly down the inside of the door.

Callum turned towards it.

"What's that?" he asked, already stepping away from the chiller.

I seized his arm.

"Rule 5: ignore any noises from the customer toilet between 22:00 and 05:00. Never investigate them."

The scratching became louder and more insistent.

Callum pulled free of my grip.

"Someone might need help."

He started towards the toilet. I moved in front of him and blocked his path.

"No. Trust me. We do not investigate noises from that toilet. Ever."

"Come on, that's ridiculous." He tried to step around me. "What if a customer has fallen over in there?"

"The toilet is empty. I checked it before we started on the chiller section. That's standard procedure. There is no one inside."

I stood my ground with my arms crossed.

The scratching stopped abruptly. A child's soft sobbing replaced it.

Callum's eyes widened.

"Can you hear that? It sounds like a child."

He tried to push past me. I planted my feet and put both hands against his chest.

"It isn't a child. It is never a child. That is how it tricks you."

For the first time, uncertainty crossed his face. The crying continued for another thirty seconds and then ceased as suddenly as it had begun.

We stood in silence.

"What was that?" Callum finally asked.

"That," I said, "is why we are paid so well."

As the training continued, I explained the other rules.

"Rule 2: no alcohol sales after 02:00, even if the customer threatens you or offers you more money. Rule 3: if the lights flicker three times in succession, go straight to the stockroom and remain there for exactly eight minutes before coming out."

Callum listened with growing scepticism.

"These sound like urban legends. Or rules from a horror film."

"Rule 4," I continued, ignoring him, "is crucial. If a regular customer comes in acting strangely, walking oddly, speaking in a flat voice or simply seeming wrong, they are no longer themselves. Do not speak to them. Do not look them in the eye. Most importantly, do not let them touch you."

"No longer themselves?" Callum laughed. "What does that even mean?"

"It means exactly what I said. You will understand when you see it."

Over the course of the evening, I showed him how to clean the self-service coffee machine, use the handheld stock terminal, prepare the nightly stock report and operate the till. Throughout it all, I kept explaining the rules and the station's unusual procedures. His responses became more dismissive each time.

"Let me get this straight," he said when I explained the 23:00 protocol. "Every night, at exactly eleven o'clock, we lock the front doors even if customers are still shopping?"

"Yes. That is Rule 6. At 22:58, we warn anyone still inside that the doors are about to be secured. Any stragglers must leave through the warded staff exit at the back."

"And that's official station policy? Locking customers in or throwing them out at eleven?"

He raised an eyebrow.

"We are not locking customers in. We are locking other things out. And yes, it is official policy. Graham will tell you the same thing. The front doors remain locked until 05:00."

Callum shook his head.

"This is horror-film nonsense. Next you'll tell me there is a special rule for a full moon, or that I mustn't get wet after midnight."

I sighed. Molly was more willing to listen to important instructions than this grown man. Even Ben knew when to take something seriously.

"Look," I said. "I have two children at home who need me. Molly and Ben do not have anyone else. I follow these rules because I want to go home to them every morning. Whether you believe the reasons or not, follow the procedures. That is all I am asking."

Callum's expression softened slightly at the mention of my children, but the doubt remained in his eyes.

At 21:45, the bell above the door rang. I immediately recognised the tall figure who entered wearing a black hooded coat.

A cold draught moved through the shop, carrying the clean smell of rain, although the night outside was dry. Reflections in the chiller doors dimmed as the figure passed them.

Callum tensed beside me, his hand moving slowly towards the telephone.

"It's all right," I said quietly as I went to the coffee machine.

I poured a large black coffee and set it on the counter without ringing it through the till. The tall man gave an almost imperceptible nod and took the cup. I could feel Callum staring as he crossed to the far corner of the shop and seemed to merge with the shadows there.

"What was that?" Callum whispered. "Why didn't you charge him?"

"That is Elias. He helps when we have problems. The free coffee is a courtesy."

"What sort of problems?"

"The sort that make the rules necessary."

For the rest of the shift, Callum practised using the till and learnt the stocking procedures. Elias remained in his corner, occasionally moving to another part of the shop but never speaking. Shortly before the shift ended, he placed his empty cup on the counter and left without a word. The smell of rain lingered for a few seconds after the door closed.

"That man gives me the creeps," Callum said once Elias had gone. "And so do all these rules. I've worked nights before. You get strange customers, certainly, but there is nothing supernatural about it."

I finished counting my till and looked directly at him.

"I am not asking you to believe in the supernatural. I am asking you to follow procedures that have kept employees at this station alive."

Callum laughed and shook his head.

"Right. Mysterious disappearances and people who aren't themselves. I appreciate you trying to make the night more interesting, but I'm a bit old for ghost stories."

As we left the shop and walked towards our cars, a knot formed in my stomach. I had seen his attitude before, and it never ended well. People who dismissed the rules did not tend to last long at Blackthorn.

"Just be careful, all right?" I said when we reached the car park. "And remember Rule 1. Never work alone."

"Of course, boss."

Callum gave me a mocking salute.

"I'll check for monsters under the till as well."

I watched him drive away, the knot in my stomach tightening. I still had to collect Molly and Ben from Mrs Ahmed next door, get them into bed and somehow sleep before doing all this again the following night.

As I started my car, I could not escape the feeling that Callum's training had been inadequate. Not because I had failed to try, but because he simply would not listen.

Some people had to learn the hard way. I only hoped Callum would survive the lesson.

Three days had passed since Callum's first shift, and I was already exhausted by his constant dismissal of everything I tried to teach him.

That night was no different. I watched him toss cans carelessly on to a shelf instead of arranging them properly.

"You'll split one of those if you keep throwing them," I said, moving to correct his sloppy work.

Callum shrugged.

"They're cans. They'll be fine."

I suppressed a sharper response. Mrs Ahmed had been unwell that day, which had forced me to take Molly and Ben to my mother's house on the far side of Ravensbrook. The extra driving had left me with barely four hours' sleep, and my patience was wearing thin.

"Let's go through Rule 2 again," I said as we approached the off-licence section. "No alcohol sales after 02:00."

"Even if they offer me a million pounds or threaten to kill me," Callum interrupted, imitating my serious tone before returning to his normal voice. "Yes, I understood the first three times."

I stopped and turned to face him.

"This isn't a joke. Two months ago, a man offered one of our cashiers four hundred pounds for a bottle of Scotch whisky at 02:30. She took the money and sold it to him. He left, then walked back in ten minutes later. Except it was not him any longer."

I kept my voice level.

"Whatever returned wearing his face broke both her arms before Elias intervened."

Callum rolled his eyes.

"More superstitious rubbish. There was probably a rational explanation. The man might have been on drugs."

"The CCTV showed him passing through the closed door. Not opening it, Callum. Passing through it."

"CCTV footage glitches all the time. I'm not buying into this horror-film nonsense simply because the place has a strange atmosphere."

The front-door bell chimed. I looked up and saw Doreen Walsh entering the shop. She came at the same time every day to buy National Lottery tickets and scratchcards.

Something was wrong with her that night.

Very wrong.

Doreen's body moved in uneven jerks. More disturbing still was her neck, which was bent at an angle no human spine could have endured without breaking. Her head lay almost sideways, her ear nearly touching her shoulder, yet she continued walking.

I seized Callum's arm hard enough to make him wince.

"What the..." he began.

"Remember Rule 4," I whispered urgently. "When regulars act strangely, they are no longer themselves."

Callum stared as Doreen moved deeper into the shop. Her head remained at that impossible angle, but her eyes, previously fixed ahead, swivelled in their sockets to look directly at us without her face turning.

"That's only Doreen," Callum whispered.

I could hear the uncertainty in his voice.

"Perhaps she has a medical condition."

"That is not Doreen any longer," I said, pulling him towards the stockroom. "We need to go. Now."

For once, Callum did not argue. We retreated to the staff area and I pulled the door almost shut, leaving only a narrow gap through which I could watch the shop.

"What are we doing?" he asked, his voice quieter than usual. "We can't simply hide in here."

"We wait until she leaves. Whatever is wearing Doreen will lose interest and go away if we do not engage with it."

Through the gap, I watched not-Doreen move along the aisles with that jerking gait. She picked up products, examined them with her head tilted impossibly far over and returned them to the wrong shelves.

It seemed endless, although it was probably no more than five minutes before she walked out without buying anything. I waited another full minute before opening the stockroom door.

"All clear."

Callum followed me back into the shop, looking around cautiously.

"That was odd, but she might have some sort of neck disorder. My aunt had this condition where..."

"Callum." I cut him off. "People with neck disorders cannot rotate their heads ninety degrees while keeping their bodies facing forwards. What we saw was no longer human."

He had no quick reply. I counted that as progress.

The rest of our shift remained uneventful until 22:55, when Imran Mahmood entered. Imran was a regular who often called in after a late shift at the distribution depot on Ravensbrook's industrial estate.

"Evening, Sarah," he said with a tired smile.

"Hello, Imran. Just so you know, we'll be locking the front doors in a few minutes."

He nodded absently and headed towards the snacks.

Callum looked confused.

"Why are we locking them? This is a twenty-four-hour shop."

"Rule 6," I reminded him. "At exactly 23:00, we secure the front doors. No exceptions."

I moved towards the entrance with the keys in my hand and watched the time on my mobile. Imran was still considering the crisps, apparently unconcerned.

"This is ridiculous," Callum said. "We can't lock a customer inside."

"We have two minutes. At 22:58, we warn any remaining customers. At 23:00 precisely, those doors are locked, whether or not someone is still inside."

I approached Imran.

"Sir, I need to lock the front doors in two minutes. If you have not finished shopping by then, I will have to let you out through the staff exit."

Imran nodded, picked up a packet of crisps and a bottle of fizzy drink and carried them to the counter.

"No problem. I'll be quick."

At 22:59, he was still at the till while Callum rang up his purchases. I stood beside the front doors with the keys ready.

"Callum, hurry," I called over my shoulder.

"He's paying, Sarah. Give us a second."

At 23:00, I immediately turned both deadlocks. Through the glass, I saw an empty forecourt and car park apart from our own vehicles. Beyond the station lights, the darkness along the road and around the service yard seemed deeper than it should have been.

"Come on," I told Imran once he had his things. "I'll show you out through the back."

Callum watched with obvious disapproval as I led Imran through the staff area to the special exit. The door had additional locks, and its frame bore weathered warding marks resembling the carvings on old boundary stones. Most people never noticed them.

"Thank you," Imran said as he stepped outside.

I promptly closed and locked the door behind him.

When I returned to the shop, Callum stood with his arms folded.

"You know how mad that looked, don't you? Locking the doors at exactly eleven and making the poor man leave through the back, as if we're running some secret operation."

"We are running a secret operation," I said. "And the front doors stay locked until 05:00."

Callum shook his head.

"What happens at eleven o'clock that is so dangerous? In three days, I haven't seen anything except an elderly woman with a stiff neck."

"You do not want to see what happens when those doors are left unsecured at 23:00. Trust me."

The next two hours were quiet. Callum cleaned the coffee machine while I restocked the Lambert & Butler cigarettes behind the counter. At about 01:00, he took cleaning supplies towards the cleaning cupboard.

I was checking stock on the handheld terminal when I heard him call from across the shop.

"Sarah, can you hear that?"

I looked up. He was standing near the cleaning cupboard with his head tilted towards the door.

I hurried over, already knowing what he had heard. Faint crying, like a child in distress, came from inside the cupboard.

"It sounds like a child," Callum said as he reached for the handle. "Perhaps one has somehow been locked in there."

I moved to stop him, but before I could reach him, the shop's reflections dimmed. A cold draught touched my face, bringing the smell of rain.

A tall figure stood directly behind Callum.

Elias had arrived without a sound, as if he had stepped out of the darkness between two shelves.

"Don't," he said quietly.

Callum leapt backwards with a startled cry and nearly collided with me. His eyes were wide as he stared at Elias, who stood motionless between him and the cupboard.

"Jesus Christ! Where did you come from?"

Elias did not answer. He seldom did. Instead, he placed one hand against the cupboard door. The crying stopped immediately.

"Callum, this is Elias," I said as colour slowly returned to Callum's face. "I told you about him on your first night. He protects us."

"Protects us from what?" Callum asked in an uncharacteristically small voice.

Elias turned his hooded head slightly towards him. His face remained hidden.

"From what exists beyond the rules," he said in a deep, quiet voice.

It was more than I had ever heard him say at once.

He removed his hand from the door and went to his usual corner. Callum watched him leave, then turned to me. For the first time since I had met him, there was no trace of smugness in his expression.

"What the hell is happening in this place, Sarah?"

"I have been trying to tell you. The rules are not superstition. They are how we survive."

Callum looked back at the now silent cupboard.

"And if I had opened it?"

I did not answer at once. I remembered the night worker, two years earlier, who had opened a door after hearing the same sound. We had never found enough of him to hold a funeral.

"You would not have finished your shift," I finally said. "And I would be training someone new tomorrow."

Callum remained quiet for the rest of the night. I could tell he did not entirely believe me, but at least he was thinking. Sometimes it was enough to make a person question their disbelief.

When our shift ended and the early shift arrived, I collected my belongings and headed outside with Callum following me.

"Sarah," he said as we reached our cars. "What Elias did tonight... I can't explain it."

"You don't have to explain it. You only have to respect it."

"But the crying in the cupboard wasn't a child."

"It is never a child."

Callum nodded slowly.

"I'll see you tomorrow night, then."

I watched him drive away, hoping the night's events had finally reached him. The rules kept us alive, but only when we obeyed them. I still had the feeling that Callum was deciding whether to believe.

A week passed after the incident with Elias and the cleaning cupboard. I had hoped it might knock some sense into Callum. Instead, his attitude towards the rules became worse.

He had seemed frightened for a short while. Now he was more stubborn than before, which worried me far more than his original ignorance.

On Tuesday night, we were working together again. I was filling the confectionery display while Callum stood behind the till, dividing his attention between his mobile and a football magazine he had brought from home.

The wall clock read 22:55.

"Callum," I called. "It's nearly 23:00. Time to secure the doors."

He barely glanced up from his mobile.

"Yes. In a minute."

I left the boxes of sweets and walked to the front.

"Not in a minute. Now. We need to warn any customers and have the doors locked by 23:00 precisely."

"Relax, Sarah. There isn't anyone in the shop."

He turned a page of his magazine.

"That is not the point. Rule 6 says the doors are locked at 23:00, whether we have customers or not."

I took out my keys and moved towards the entrance. The seconds passed slowly as I looked outside. The forecourt was empty apart from our cars, but that did not matter.

Rules were rules, especially this one.

"Put that down and help me check the shop," I said, urgency tightening my voice.

Callum gave a theatrical sigh, but set aside his mobile.

"Fine. I'll check the back aisles."

At 22:59, I stood by the front doors and watched the seconds count down on my mobile. Callum was meant to be completing the final sweep, but I could not see him anywhere.

The display changed to 23:00. I reached for the locks, then hesitated.

"Callum? Have you finished checking?"

There was no answer.

I should have secured the doors immediately, but I needed to know whether he had found someone.

"Callum!" I called again, louder.

At last, his voice came from the rear of the shop.

"Yes. All clear."

I turned back to the doors and saw that it was already 23:01. Fear struck me at once. I hurriedly engaged both deadlocks.

By the time Callum wandered back to the front, unconcerned, it was 23:02.

"There was no one back there. I told you we were empty."

"Those doors were supposed to be locked at 23:00," I said tightly. "It is now 23:03."

"So we're a few minutes late. It isn't a disaster."

He shrugged and returned to the counter. I followed him, frightened and furious.

"It is a disaster. Three minutes late, Callum. Do you have any idea what can happen in three minutes?"

"Let me guess. Demons crawl through the doors and eat our souls."

He rolled his eyes.

"Last year," I said, lowering my voice, "a woman called Leanne Briggs was fifteen minutes late securing the entrance. They found her with her skin turned inside out."

Callum's smile faltered before he forced a laugh.

"Come on, Sarah. Skin turned inside out? That isn't physically possible."

"I saw the photographs. Graham showed them to all of us as a warning."

I was not lying. Images of Leanne Briggs's body had haunted my dreams for weeks. Whatever came through the doors had not merely killed her. It had unmade her.

Something in my tone reached him. He did not dismiss me immediately. Instead, he looked towards the now secured doors and swallowed.

"You're serious."

It was barely a question.

"Deadly serious. Three minutes late is three minutes too many."

Callum said no more about it that night, but I noticed him watching the doors more often, particularly when the wind rose and branches scraped against the glass.

Thursday's shift began normally. We had a steady succession of customers until midnight, followed by the usual late-night lull. Callum had been quieter than usual and was following procedures without much complaint. I hoped the story of Leanne Briggs had finally made an impression.

At 01:30, without warning, the lights went out.

Not only the shop lights. Everything failed. The lamps over the pumps, the roadside sign and the emergency lighting all died at once. The shop fell completely dark.

"Power cut," Callum said from somewhere near the till.

I fumbled for my mobile and switched on its torch.

"This is not normal. The backup generator should have started automatically."

As my eyes adjusted, I made out Callum's silhouette moving towards the front windows.

"It looks as though the whole road is out," he said, peering outside.

"Get away from the glass," I warned as I moved towards him.

"Why? I'm only checking whether..."

A violent impact cut him off. Something had struck the doors from outside.

Another blow followed. Then another.

Multiple bodies were hurling themselves against the entrance.

"Callum, get back."

I caught his arm and pulled him away just as the beam of my mobile torch swept across figures pressing against the glass. Their features were distorted, their faces stretched and twisted in ways no human flesh could bend.

"What the hell?" Callum gasped, trying to stare at them.

I dragged him farther back and put myself between him and the doors.

"Do not look directly at them," I hissed. "Keep your eyes lowered or shut."

The pounding became more frantic. The doors rattled in their frames, and the torch beam trembled with my hand. At the edge of my vision, I could see several figures pressed against the glass, their hands spread flat upon it.

"What are they?" Callum whispered, all his usual arrogance gone.

"I don't know. And I don't want to find out."

Something moved at the back of the shop. The reflections in the darkened chiller doors dimmed still further. A cold current of air carried the smell of fresh rain.

A tall figure emerged from the shadows and walked calmly towards us.

Elias.

I had not seen him enter, but somehow he was there when we needed him.

He passed us without speaking and approached the entrance. The moment he reached the doors, the figures outside recoiled. They fled into the darkness beyond the forecourt, vanishing as swiftly as shadows beneath a switched-on light.

The pounding ceased.

Seconds later, the power returned. The fluorescent tubes flickered into life, the chillers resumed their hum and the electronic till rebooted with a series of beeps. It was as though nothing had happened.

Elias stood at the doors for another moment before walking to his usual corner. He neither spoke nor looked at us, but his message was plain.

He had reinforced the barrier. He had protected us.

Callum leant against the counter, his face pale.

"What just happened?" he asked, hardly louder than a whisper.

"That is why we lock the doors at 23:00."

For the rest of the shift, Callum remained subdued. He jumped at small noises and kept glancing towards Elias's corner as if checking that he was still there.

When morning came and the early shift arrived, Callum almost ran to his car. I caught up with him in the car park.

"Are you all right?"

He took a deep breath.

"That was... I don't know what that was."

"It was what I have been warning you about. The rules exist for a reason."

He nodded slowly.

"Yes. I understand that now."

Then he hesitated and looked back at the shop.

"Those things at the window couldn't have been real, though, could they? Perhaps it was some teenagers playing a prank, and power cuts do happen."

I stared at him in disbelief. Even after everything he had witnessed, he was still trying to rationalise it.

"Those were not teenagers, and Elias did not simply happen to arrive at the exact moment we needed help."

"I'm not saying nothing strange happened," he replied defensively. "It was certainly unsettling. But there are rational explanations for power cuts and people banging on doors."

I gave up. Some people would never believe, regardless of what they saw with their own eyes.

"Promise me that you will keep following the rules, even if you refuse to believe the reasons."

"Of course," he said, but I could tell he was only humouring me.

On Sunday afternoon, my mobile buzzed while I helped Molly with her science project. Callum had sent me a message.

Can I cover your Monday night shift? Need extra hours this week.

I frowned and typed a reply.

You mean with Lucy?

Lucy Shaw was an established relief colleague and Callum's scheduled partner for Monday night.

His response appeared a moment later.

No. Just me. Lucy called in sick.

My stomach dropped. I rang Callum immediately instead of replying by text, but he did not answer. I tried again. Nothing.

I sent another message.

Rule 1. Never work alone. Wait until I find someone who can cover the shift with you.

Three dots appeared on the screen.

No one follows these rules when you're not there anyway. Nothing ever happens.

I rang again. He ignored the call.

Then I messaged Graham Hargreaves and explained the situation. He replied that he would deal with it, but my unease remained.

Callum, do not work alone. I am serious. It is dangerous.

The three dots appeared, vanished and appeared again.

Relax, Sarah. I'll be fine. See you Tuesday.

I stared at the mobile as dread washed through me. Molly looked up from her papier-mache model of the solar system and noticed my expression.

"Mum, is everything all right?"

I forced a smile for my daughter's sake.

"Yes, love. It's only something at work."

But it was not all right. Callum intended to break the most important rule, and there was nothing more I could do to stop him.

I pushed open the door to Blackthorn's forecourt shop at 05:55 on Tuesday morning, five minutes before my shift was due to begin.

The fluorescent lights were flickering irregularly.

Something was wrong.

The doors should still have been locked. Callum should have been inside, waiting to hand over the till after opening them at 05:00 with the authorised keys.

"Callum?" I called.

My voice sounded far too loud in the empty shop.

There was no answer. The silence felt heavy, pressing against my ears as I took several cautious steps inside.

At first glance, everything appeared normal. The shelves were stocked, the coffee machine hummed and the closed till looked intact. But Callum was not behind the counter.

"Callum, are you here?"

I moved no farther than I had to.

Then I noticed the drops on the floor.

Under the unstable lights they looked almost black. They formed a trail leading from the counter towards the customer toilet.

My stomach tightened. I followed the trail with my eyes, not my feet. The toilet door was closed.

I took out my mobile and rang Graham immediately. The call went straight to voicemail.

"Graham, it's Sarah. Something is wrong at the station. Callum isn't here. The front doors were unsecured, and there is... there is something on the floor. I am following protocol and leaving now."

My hand shook as I ended the call.

The protocol was clear. If anything appeared wrong when an employee arrived for a shift, they were to leave immediately and contact management. No exceptions.

I backed towards the entrance, keeping my eyes on the toilet door. The trail of dark droplets shone beneath the stuttering lights. I did not want to consider what it might be, but my mind supplied the answer anyway.

As I reached the entrance, the lights flickered more violently, then steadied.

The drops were not black.

They were a deep and unmistakable red.

I turned and ran to my car, fumbling with my keys before I managed to unlock it. Once inside, I locked every door and started the engine with trembling hands.

As I drove off the forecourt, I glanced into the rear-view mirror. The shop lights continued to flash on and off. For a fraction of a second, I thought I saw a tall figure standing in the doorway.

The lining of its coat was pale, a sharp flash against the darkness.

When I looked directly back, there was nothing there.

The drive home took fifteen minutes but felt like hours. My thoughts raced through possibilities, each one worse than the last.

Callum had broken Rule 1. He had worked alone.

Whatever had happened was the consequence of that choice.

Molly and Ben were eating breakfast when I walked in. Mrs Ahmed from next door had stayed overnight to look after them, as she often did during my shifts.

"Mum!"

Ben jumped up from his cereal, milk running down his chin.

"You're home early."

Molly sensed at once that something was wrong.

"Did something happen at work?"

Mrs Ahmed looked up from pouring apple juice, her eyebrows raised.

"There was a problem at the station," I said carefully as I set down my handbag. "I had to leave early."

"What sort of problem?" Molly asked, watching me closely.

I forced a smile.

"A maintenance problem. Nothing for you to worry about."

Mrs Ahmed gathered her things, and I walked her to the door, thanking her for staying with the children.

"Is everything all right, Sarah?" she asked quietly. "You look very pale."

"I'm fine," I lied. "Only tired. Thank you again for having them."

After she left, I made coffee with shaking hands and sat at the kitchen table, trying to look normal for the children's sake. Ben chattered about a dream he had had, while Molly continued studying my face with concern.

"Mum, you're acting strangely," she said at last. "Did something frightening happen?"

I looked at my daughter and wondered how much I could tell her. Molly had always been intuitive, noticing things other children her age missed.

"I'm worried about someone I work with," I admitted. "He might be in trouble."

"The one who doesn't believe in the rules?"

I blinked. I had not realised how much I had said about Callum's attitude in front of the children.

"Yes. That one."

Molly nodded solemnly.

"You always say rules keep us safe."

"They do."

I reached across the table and squeezed her hand.

"That is why it is so important to obey them."

The morning crawled past. I rang Graham three more times, but every call went to voicemail.

I helped the children with their homework, made lunch and tried to behave as if everything were normal while checking my mobile every few minutes. By early afternoon, Ben was absorbed in a video game and Molly was reading beside me on the sofa.

At 15:42, my mobile rang. I did not recognise the number, but I answered immediately.

"Hello?"

"Is that Sarah Mercer?" a man's voice asked.

"Yes, speaking."

"Ms Mercer, this is Detective Constable Oliver Grant from Ravensbrook police station. I understand that you work at Blackthorn Service Station on Hawthorn Road."

My throat tightened.

"Yes. I need to ask you some questions about your colleague, Callum Price. Would it be possible for you to come down to the station this afternoon?"

I glanced at Molly, who had looked up from her book.

"I have my children with me. Could you tell me what this is about first?"

There was a pause on the line.

"Ms Mercer, I'm afraid Mr Price's body was found behind the shop this morning. Given that you were due to relieve him, we'd like to speak with you."

I felt dizzy. I gripped the edge of the sofa to steady myself.

"His body?" I repeated, my voice barely audible.

"Yes. I'm sorry to tell you this way. Would 17:00 suit you? We can arrange for someone to look after your children if necessary."

"No, I... I have a neighbour who can watch them. I'll be there."

After hanging up, I sat motionless, the mobile still clutched in my hand. Molly put down her book and moved closer to me.

"Mum, what happened?"

I looked at my daughter, trying to find words that would not frighten her.

"The colleague I was worried about. Something bad happened to him."

"Is he dead?" she asked directly.

I nodded slowly. "Yes, love. He is."

Molly was quiet for a moment.

"Because he didn't follow the rules?"

"I think so," I whispered.

Mrs Ahmed agreed to watch the children again while I went to Ravensbrook police station. Before leaving, I hugged Molly and Ben tightly and promised I would be back soon. Molly held on particularly hard, as if she understood the danger I faced every night at work.

The police station was busy when I arrived. An officer directed me to a small interview room, where Detective Constable Oliver Grant waited with a notepad.

"Ms Mercer, thank you for coming in," he said, indicating the chair opposite him. "I understand you found the shop in an unusual condition this morning."

I sat down and folded my hands in my lap to stop them shaking.

"Yes. The doors were unlocked when I arrived, and Callum wasn't there. There were drops on the floor. Red drops."

"And you telephoned your manager and left immediately."

"Yes. That's our protocol if anything seems wrong."

DC Grant nodded and made a note.

"Can you tell me about your last interaction with Callum Price?"

I explained the text messages and how Callum had insisted on working alone despite my warnings.

"And why exactly were you so concerned about him working alone?" Grant asked.

"It's against station policy. Rule 1 is never work alone, especially on the overnight shift."

"Why is that rule so important?"

I paused, knowing how it would sound.

"There have been incidents at Blackthorn. People who worked alone disappeared or were found dead."

Grant's face remained neutral, but I could see the doubt in his eyes.

"What sort of incidents?"

"Two years ago, an employee named Nathan Cole disappeared during a solo overnight shift. Last year, a woman named Leanne Briggs was found dead after failing to lock the doors at 23:00. There are six specific rules we follow to stay safe."

"What are they?"

I took a deep breath and listed them in order.

"Rule 1: never work alone. Rule 2: no alcohol sales after 02:00. Rule 3: if the lights flicker three times, go into the stockroom and wait for eight minutes. Rule 4: avoid regular customers who act altered, because they aren't themselves any more. Rule 5: ignore noises from the customer toilet between 22:00 and 05:00. Rule 6: lock the front doors at exactly 23:00 and keep them locked until 05:00. No exceptions."

As I spoke, Grant's expression shifted from neutral to incredulous.

"Ms Mercer, those sound like superstitions, not safety procedures."

"They're not superstitions," I insisted. "They keep us alive."

"Did Callum Price believe in these rules?"

"No. He thought they were ridiculous. He called them horror-film nonsense and superstitious rubbish."

Grant made another note.

"Ms Mercer, I need to tell you how Callum Price died. His body was found dismembered behind the shop. His limbs and head had been separated from his torso."

I closed my eyes, feeling sick.

"I told him not to work alone."

"Do you know anyone who might have wanted to harm Mr Price?"

I shook my head. "No. Callum was new. He'd only been working at Blackthorn for about two weeks."

"And these rules you've mentioned are official station policy?"

"Yes. Graham Hargreaves, our manager, is very strict about them."

Grant wrote something down.

"We'll be speaking to Mr Hargreaves as well. In the meantime, I need to ask where you were between midnight and 05:00 last night."

"I was at home with my children. My neighbour, Mrs Ahmed, stayed over to watch them while I slept. She can confirm I was there all night."

The detective constable nodded.

"We'll check that. One more question. Does the station's CCTV record continuously?"

"Yes. Graham has access to all the footage."

"Thank you for your time, Ms Mercer. We'll be in touch if we have further questions."

As I stood to leave, Grant added, "I'd advise you not to discuss the details of Mr Price's death while the investigation is under way."

I nodded and left.

Callum's death weighed heavily on me. I had tried to warn him. I had tried so hard.

The following morning, Graham Hargreaves rang me at 09:00.

"Sarah, I need you to come to the station. The police are reviewing the CCTV from Monday night."

An hour later, I sat in Graham's cramped office with DC Grant and another officer. Graham looked grim as he brought up the footage on his computer.

The recording showed Callum alone in the shop at about 22:30 on Monday. He was reading a football magazine at the till, occasionally checking his mobile. At 22:55, he looked at the clock but made no move towards the doors. The crucial moment at 23:00 came and went. The doors remained unlocked.

At 23:17, a hooded person appeared outside the shop. The figure wore a dark outer coat, but its pale lining flashed whenever it moved. Its gait was unnatural, each step landing a fraction too late, as though the body were copying someone walking. Callum looked up as it entered.

They spoke, although the CCTV had no sound. Callum seemed relaxed. He even smiled as he put the visitor's visible purchases through the till - crisps, a bottle of fizzy drink and a packet of sweets.

At 23:32, the customer-toilet door opened by itself. Callum noticed and looked confused. The hooded visitor pointed towards it. Callum shook his head, but the figure gestured again, its arm bending too slowly at the elbow.

A moment later, sounds must have come from the toilet because Callum turned sharply towards it. The visitor walked towards the open door, the pale lining of its coat showing again. After a pause, Callum followed.

The footage showed both of them entering the customer toilet. The door closed behind them.

For five minutes, nothing happened. Then the lights began to blink. The camera image warped, broke into static and cut out completely.

When the footage returned at 00:17, the shop was empty. The customer-toilet door was shut. Dark drops led from it through the staff area towards the warded staff exit.

Graham stopped the recording.

DC Grant looked troubled.

"Can you identify the hooded figure?" he asked Graham.

"No. And that was not Elias, if that's what you're thinking," Graham replied. "The pale coat lining, the way it walked, the purchases - none of that was him. Elias never buys anything, and he never enters the customer toilet."

Grant turned to me.

"Who is Elias?"

"He helps when there are problems at the station," I explained. "He's tall and wears a black hooded top, but he's protective. He wouldn't have hurt Callum."

Grant did not look convinced.

"We'll need to question this Elias as well."

"Good luck with that," Graham muttered.

After the police had left, Graham asked me to stay. He looked older than usual, the lines in his face deeper.

"You followed the rules, Sarah. You survived. Callum didn't."

He sighed heavily.

"I've hired someone new. Can you begin her training tomorrow?"

"Someone new already?" I asked, startled by how quickly Callum had been replaced.

"Blackthorn can't be understaffed, not even for a night. Her name is Niamh Foster. She's twenty-six and has good references. She starts tomorrow night."

He handed me a file. I took it, feeling numb.

"What do I tell her about Callum?"

"The truth," Graham said simply. "The rules keep you alive. Breaking them gets you killed."

I nodded slowly, thinking of Molly and Ben waiting at home. I needed this job. Blackthorn paid nearly twice the usual local forecourt-shop rate, and as a single mother I could not simply walk away from that money.

But there was more to it now. I understood that what we did at Blackthorn Service Station mattered. The rules were not only there for our safety. They were there for everyone beyond those locked doors.

"I'll be here," I said. "And I'll make certain Niamh understands the rules better than Callum did."

Graham nodded, visibly relieved.

"Good. I knew I could count on you, Sarah."

As I drove home, I could not stop thinking about Callum's final moments. Had he realised his mistake when it was too late? Had he finally believed in the rules as whatever came through the customer-toilet door tore him apart?

I would never know. All I could do was make certain the next employee understood what was at stake and hope she believed me before it was too late.

Two weeks had passed since I had found those red drops on the floor at Blackthorn. Two weeks since DC Grant had shown me the CCTV footage of Callum following that false hooded visitor into the customer toilet. Two weeks since they had found what was left of him behind the shop.

I still had nightmares about it. Not about Callum's dismembered body - I had not seen that, thank God - but about what might have happened during those missing minutes. What had come through that door? What had Callum seen at the end?

Tonight was my third shift training Niamh Foster. She stood beside me at the till, carefully counting out change for a customer who had bought Lambert & Butler cigarettes and a National Lottery ticket. Her movements were precise and methodical, nothing like Callum's casual disregard.

"Have a good night," Niamh said.

The customer nodded and left. The door chimed as it closed behind him.

I looked at the clock. It was 21:47. We still had plenty of time before the 23:00 lockdown.

"You're doing brilliantly," I told her. "Much better than I..."

I stopped myself.

"Than Callum?" Niamh finished for me, tucking a strand of dark hair behind her ear. "It's all right. Graham told me what happened to him."

I nodded, relieved that I did not have to skirt around the subject.

"Did he tell you everything?"

"He said Callum broke the rules. That he worked alone. And..." She hesitated. "Something got him."

"That's the short version. The important part is that the rules keep us alive. All six of them."

Unlike Callum, Niamh had taken the rules seriously from the first night. When I explained Rule 1, never work alone, she nodded solemnly. When I told her about Rule 6 and the 23:00 lockdown, she asked practical questions about the keys, the deadbolts and the authorised use of the warded staff exit rather than demanding to know why. When I mentioned Rule 5 and the noises from the customer toilet, she simply asked what she should do if she heard them.

It was refreshing. More than that, it was a relief.

"Let's finish restocking the chillers," I suggested. "Then I'll show you how to run the nightly stock report."

We worked side by side, placing cans of strong iced coffee and bottles of fizzy drink in neat rows. Niamh was quiet but attentive, asking questions when necessary and otherwise concentrating on the job.

At 22:30, we moved into the small office beside the stockroom so I could demonstrate the stock-control system. I logged in and opened the nightly report.

"It's fairly straightforward," I explained. "You enter the figures from the handheld stock terminal, and the system works out what needs ordering."

Niamh leaned over my shoulder, watching me move through the screens.

"What happens if the numbers don't match?"

"Good question. If there's a discrepancy, you record it here." I pointed to a field on the screen. "Graham reviews every report in the morning."

A loud bang interrupted us.

We both jumped and turned towards the office door.

"What was that?" Niamh whispered.

I listened. Another bang came, followed by a violent rattling from the front of the shop.

"Stay here," I said, rising. "I'll look."

I walked cautiously into the main shop. Everything appeared normal until I saw the customer-toilet door shaking in its frame. The rattling grew more violent, as though someone - or something - was trying to force its way out.

I had told Niamh to stay put, but she followed me. She stopped a few metres behind me, frozen, her eyes wide.

"Is someone in there?" she asked, barely audible.

I shook my head. "No. It was empty when we checked earlier."

I looked at the clock.

"It's 22:42. Remember Rule 5? Never investigate noises from the customer toilet between 22:00 and 05:00."

The door rattled harder, its hinges creaking under the strain. A low, guttural sound came from inside, neither quite human nor quite animal.

Niamh stepped back.

"Shouldn't we do something?"

"Yes," I said, turning away from the door. "We keep working."

I walked calmly to the till and began organising the receipt rolls as though nothing unusual was happening. After a moment's hesitation, Niamh joined me, although her hands trembled as she straightened the confectionery display beside the counter.

The rattling continued, growing more insistent. The toilet door bulged slightly, as though something massive were pressing against it from within.

"How can you be so calm?" Niamh whispered.

"Practice," I admitted. "And knowing that as long as we follow the rules, we'll be all right."

A cold draught swept through the shop. The reflections in the front windows dimmed, and I caught the clean smell of rain although the forecourt outside was dry.

The entrance chimed.

Elias walked in wearing his familiar black hooded top. He moved silently towards the self-service coffee machine, as he always did. I left the till and prepared his usual drink.

"Black, no sugar."

As I handed it to him, I lowered my voice.

"We could use some help," I said, nodding towards the customer toilet. "If you don't mind."

Elias took the coffee. His fingers brushed mine, oddly cool against my skin. He nodded once and turned towards the shaking door.

Niamh watched with wide eyes as he walked directly up to it. He placed his free hand flat against the wood, and the rattling stopped at once.

The silence was sudden and absolute.

Elias opened the customer-toilet door and stepped inside, closing it behind him. For a long moment, nothing happened.

Then the door opened again and he emerged. As he passed, he set the cup on the counter and nodded to me. Another faint draught touched my face, carrying the smell of wet tarmac, and he left the shop.

Niamh stared at the customer-toilet door, now perfectly still on its hinges.

"What did he do?"

"I don't know exactly," I said. "But Elias helps with problems. That's what he does."

She looked at me with a mixture of fear and awe.

"Is he human?"

I hesitated. "I don't think so. Not entirely."

Niamh absorbed that with remarkable calm.

"And the thing in the toilet wasn't human either."

"No. And that's all you need to know for now."

We finished our tasks in silence. At 22:55, I reminded her about the lockdown procedure. She helped me check the entire shop for customers, then stood beside me as I secured both deadbolts at precisely 23:00.

"Perfect timing," she said, checking her watch.

"Always," I replied. "Three minutes late is three minutes too many."

The rest of the night passed without incident. We cleaned, restocked and completed the reports. Niamh asked sensible questions and followed every instruction carefully.

By 02:00, I felt confident that she could survive working at Blackthorn.

A key turned in the secured front doors.

I looked up as Graham Hargreaves unlocked the deadbolts with his authorised keys, entered and immediately relocked both doors behind him. He rarely visited during overnight shifts, preferring to handle station business in daylight.

"Evening, Sarah. Niamh," he said, nodding to each of us.

He looked tired, the lines around his eyes deeper than usual.

"Is everything all right?" I asked.

"I need to speak to you privately. Niamh, can you watch the front for a few minutes?"

"Of course, Mr Hargreaves."

Graham led me to the office and shut the door behind us. He took the chair behind the desk and indicated the other one.

"You've done well with Niamh," he said. "She's learning quickly."

"She listens," I replied. "Unlike Callum."

Graham nodded grimly. "Callum's death was unfortunate, but it wasn't unexpected. Some people refuse to believe until it's too late."

He opened a drawer and removed a thick folder.

"Sarah, you've been with us for three years. You've followed the rules, trained new employees and survived. That's more than most can say."

"I have children to go home to," I said simply. "The rules keep me alive for them."

"Yes, they do." Graham leaned forwards, his expression grave. "But it's time you understood why the rules exist."

He opened the folder, revealing photographs, diagrams and images of weathered warding marks resembling those carved into old boundary stones.

"Blackthorn isn't merely a petrol station and twenty-four-hour forecourt shop," he said. "It stands over a weak point between worlds, a thin place in the fabric of reality."

I stared at him, trying to process the words. Part of me had always suspected something like this, but hearing it said so plainly was still shocking.

"The rules don't only keep you safe," Graham continued. "They prevent what is on the other side from crossing. The 23:00 lockdown happens when the boundary is weakest. The noises in the customer toilet are made by something trying to create an opening. The regulars who aren't themselves have been influenced by what lies beyond."

I thought of Doreen Walsh with her impossibly bent neck and of the figures that had pressed themselves against the glass doors during the first major power cut.

"And Elias?" I asked.

Graham's expression softened slightly.

"Elias isn't human, as you've probably guessed. He's a guardian who chose to help us. There are others like him, but most of them have no interest in our world. Elias is different."

"He protects us."

"He protects the boundary," Graham corrected. "We happen to be on this side of it."

I took a deep breath, trying to absorb it all.

"Why are you telling me now?"

"Because things are getting worse," Graham said quietly. "The incidents are becoming more frequent. The entities on the other side are growing more aggressive. We need staff who understand what they're truly guarding."

"Does Niamh know?"

Graham shook his head. "Not yet. I wanted to tell you first. You've earned the right to know."

He closed the folder and handed it to me.

"Take this home. Study it. The more you understand, the better your chance of surviving."

I accepted it. "Thank you for trusting me."

"You've proved yourself trustworthy," Graham said, standing. "Now let's get back out there before Niamh begins wondering what we're discussing."

When we returned to the front, Niamh was helping a lorry driver find the cans of strong iced coffee. Graham unlocked the secured doors with his keys to leave, then pulled them shut and relocked both deadbolts from outside. He checked them before walking away across the forecourt.

"Everything all right?" Niamh asked after the lorry driver had gone.

"Yes," I said, tucking the folder into my bag. "Just a performance review."

The rest of the night was quiet. At 03:45, Niamh took her break while I watched the till. At 04:00, the entrance bell chimed as another lorry driver came in through the doors, which Graham's authorised entry had left secured until the normal 05:00 opening and which I admitted with the controlled night-access release behind the till.

The man was tall and broad-shouldered, with four days of stubble and bloodshot eyes.

"Packet of Lambert & Butler and a 70 cl bottle of vodka," he said, placing a twenty-pound note on the counter.

Niamh, who had just returned from her break, moved to fetch the cigarettes while I dealt with the money.

"I'm sorry, sir," I said, "but we can't sell alcohol after 02:00. Station policy."

The man's expression darkened.

"It's only a bottle of vodka. No one's going to know."

"I'm sorry," I repeated firmly. "We can sell you the cigarettes, but not the alcohol."

"This is rubbish," he growled. "I've been driving all night. I need something to help me relax when I reach the roadside hotel."

"We have other options," Niamh suggested, pointing towards the chilled drinks. "Or coffee."

The man slammed his fist on the counter.

"I don't want coffee. I want vodka."

I stepped slightly in front of Niamh, keeping my expression calm.

"Sir, we cannot sell alcohol after 02:00. It's a licensing restriction."

It was not. The restriction was a supernatural shop rule, but claiming it was part of the premises licence was easier than explaining the true danger.

"The law?" he sneered. "You think I care about the law?"

As he spoke, something happened to his face. The skin around his mouth stretched, exposing too many teeth. His already bloodshot eyes began leaking a dark liquid that did not resemble tears.

"Give me the vodka," he said, his voice distorting and falling by an octave. "Now."

I seized Niamh's arm and pulled her back from the counter.

"Sir, I'm going to have to ask you to leave."

The man, or whatever was using his body, leaned across the counter. His face shifted in ways no human face could. The air filled with the smell of rotting vegetation and scorched wiring.

"You know what I am," it said, its voice now a guttural growl. "You know what I need."

I kept retreating, taking Niamh with me.

"We can't help you. Please leave."

The creature snarled, producing a sound no human throat could make. It reached across the counter. Its arms stretched impossibly far, its fingers lengthening into hooked, claw-like shapes.

"The bottle," it hissed. "Give me the bottle."

I thought of Rule 3. The lights had not flickered three times, so the rule had not technically been triggered, but the principle offered our safest response: retreat to the stockroom, secure the door and give the danger time to pass.

"Niamh," I whispered, "when I say run, go to the stockroom and lock the door. Stay there for eight minutes, no matter what you hear."

She nodded, pale but determined.

The creature began climbing over the counter, moving in jerks like a puppet with tangled strings.

"Run!" I shouted, pushing Niamh towards the stockroom while I moved in the opposite direction to draw the thing's attention.

It turned towards me, its mouth opening wider than any human jaw could stretch. I backed away, keeping the shelving aisles between us.

"You can't have it," I said firmly. "You don't belong here. Go back."

The creature produced a sound somewhere between laughter and a scream. It advanced, knocking over displays as it came. I continued retreating, leading it away from the stockroom where Niamh had taken refuge.

For several terrifying minutes, I remained barely beyond its reach while holding its attention. Its movements became more erratic and desperate. The distortion spread across its face until the lorry driver's features were scarcely recognisable beneath the thing wearing his skin.

Then, as abruptly as it had begun, the creature stopped.

It tilted its head at an impossible angle, listening to something I could not hear. The reflections in the shop windows dimmed. A cold draught brushed my face, carrying the smell of rain.

Fear - unmistakable, genuine fear - crossed the creature's warped features.

It backed towards the door, its dark eyes darting around the shop. Without another word, it turned and fled. I released the controlled lock, and it wrenched the door open and ran on to the forecourt. The bell chimed cheerfully as the door swung shut, and the night lock engaged again.

I stood frozen for a moment. Then I hurried to the stockroom and knocked three times so Niamh would know it was me.

She opened the door, still pale but composed.

"Is it gone?"

"Yes. It left."

"What was that thing?" she asked, her voice steady despite what she had witnessed.

"Something that doesn't belong in our world. Something the rules keep out most of the time."

Niamh took a deep breath.

"I thought Callum was simply being difficult when he refused to believe you. I couldn't understand how anyone could dismiss what you were saying. But that... that was..."

"I know," I said gently. "It's a lot to take in."

She looked straight into my eyes.

"I believe everything now," she whispered. "Every rule. Every warning. All of it."

I nodded, reassured. Niamh would survive. She understood what was at stake.

"Good," I said. "Because believing is what keeps us alive."

As dawn approached and our shift neared its end, I thought about the folder Graham had given me, the weak point between worlds and Elias's role as guardian. I thought about Molly and Ben sleeping safely at home, unaware of what their mother faced each night at work. And I thought about Callum, who had not believed until it was too late.

Niamh would be different. She would survive, and so would I.

One month after learning the truth about Blackthorn Service Station, I found myself settling into a new routine. Graham's folder had become part of my life. I studied it carefully, learning about the thin places between worlds, the kinds of entities that tried to cross and the weathered warding marks that strengthened the barriers.

Knowledge had not made the job less dangerous, but it made the danger easier to understand.

Niamh had proved herself a quick learner and a reliable partner. Unlike Callum, she followed the rules without question, having seen first-hand what happened when they were tested. We developed an easy rhythm during our overnight shifts, moving around one another with the practised efficiency of people who understood exactly what was at stake.

Tuesday night began like any other. The shop had been busy until about 22:00, when customer traffic slowed to a trickle. Niamh was restocking the sweets aisle while I counted the till in preparation for the 23:00 lockdown.

"How are Molly and Ben?" Niamh asked as she arranged chocolate bars in neat rows.

"Good," I said, sorting banknotes into the till drawer. "Molly got the top mark on her science project. The papier-mache model of the solar system survived the journey to school, somehow. Ben has lost another tooth."

"That's lovely. Molly's the one who realised something was wrong with Callum before you did, isn't she?"

I nodded, remembering how perceptive my daughter had been.

"She notices things. Sometimes I think she knows more about what happens here than I've told her."

The clock read 22:56. I finished counting the till and went to the front doors, checking the forecourt for any last-minute customers. The car park was empty apart from our two cars.

"Nearly time," I called to Niamh. "Can you check the back aisles?"

She nodded and disappeared around the crisps display. I took out my keys, ready for the lockdown procedure we performed every night.

At 22:58, the lights went out.

Not only the shop lights. Everything died at once: the roadside lamps, the illuminated open sign and even the glow inside the refrigerated cabinets.

The darkness was complete.

I waited for the emergency lighting to start.

It did not.

"Sarah." Niamh's voice came from somewhere in the darkness, tight with fear.

"Stay where you are," I called, pulling out my mobile.

The screen lit my face with a weak blue glow that barely penetrated the blackness. I checked the time.

22:59. One minute until lockdown.

I switched on the mobile torch and aimed it towards the front doors. Its beam seemed feeble in the unnatural darkness.

"What's happening?"

Niamh had found her way back to me, her own mobile providing a small circle of light.

"I don't know, but we must lock the doors now."

A scratching noise came from the customer toilet, the familiar sound that always meant trouble.

Then another scratching joined it from the cleaning cupboard on the opposite side of the shop.

"They're trying to cross through several places at once," I said, moving quickly towards the entrance.

Niamh's torch beam swept across the glass and stopped.

"Sarah," she whispered. "Look."

Outside, barely visible in the darkness, stood figures. Not one or two, but dozens. Their outlines were indistinct, shifting slightly in the night. They crowded close to the glass and watched us with eyes that reflected our torch beams like animals caught in headlights.

"Help me," I said, fitting my key into the first deadbolt.

The figures began to move, pushing against the glass. Hands, or things resembling hands, flattened against the transparent surface and left wet smears in our torchlight.

Niamh pulled the second key from her pocket with trembling fingers. I locked the first deadbolt as she fitted her key into the second.

My watch beeped.

23:00 exactly.

Niamh turned her key. The second deadbolt locked with a solid click.

The figures outside became still.

Then they all began hammering on the glass at once. The doors shook under the assault. A wail rose from the forecourt, neither human nor animal, a sound that made my teeth ache and my skin crawl.

"What do we do?" Niamh asked, backing away.

A cold draught moved beside us. Our reflections dimmed in the glass, and the scent of rain cut through the stale shop air.

A tall figure appeared at my shoulder as though it had stepped directly out of the darkness. I almost screamed before recognising the black hooded top.

"Elias," I breathed, relief flooding through me.

He nodded once and pointed towards the back of the shop.

"Go," he said quietly. "Now."

We did not argue. Niamh and I hurried towards the stockroom, using our mobile torches to find the way. The scratching from the customer toilet and cleaning cupboard had grown louder. Both doors bulged in their frames, as if massive bodies were pressing against them.

Elias followed, moving quickly and silently. As we passed each threatened door, he laid one hand against it. Whatever waited beyond fell quiet for a moment, but the renewed pressure began almost as soon as he moved away. He could reinforce the boundary, I realised, but the attacks were too coordinated for him to hold every point alone.

I pushed open the stockroom door, expecting darkness. Instead, a warm amber glow met us.

Graham stood inside among several battery storm lamps fitted with amber filters. He looked grave but unsurprised.

"Right on time," he said, beckoning us in.

Elias followed and closed the stockroom door firmly behind him.

"What's happening?" I asked, trying to keep my voice steady for Niamh's sake.

"This is your final test," Graham said. "They're attempting a coordinated breach through several access points."

A tremendous crash came from the shop, followed by breaking glass. Niamh flinched, her eyes wide.

"The doors..."

"Elias reinforced the front boundary before he came to find you," Graham said. "It will hold for the moment."

He crossed to a metal cabinet I had never noticed before and unlocked it with a key from his pocket. Inside were more storm lamps, bottles of water and objects that resembled weapons, though none was of a kind I recognised.

Graham removed two stubby inspection-torch devices and handed one to each of us. Weathered warding marks resembling those on old boundary stones had been engraved into their casings, matching the symbols in his folder and those carved around the warded staff exit.

"What is this?" Niamh asked, turning the device in her hands.

"Protection," Graham replied. "Point it at the centre of anything that gets through and press the button before it anchors itself to a person, animal or object. It won't kill them, but it will force them back to their side."

Screams echoed through the shop, inhuman sounds that prickled my skin.

Elias stood beside the door, his head tilted as though listening.

"I don't understand," I said. "Why tonight? Why all at once?"

Graham met my gaze.

"Because you're ready now, both of you. You've proved that you can follow the rules and believe before you fully understand. Now you need to see what you're truly guarding against."

He sat on a folding chair and motioned for us to do the same.

"You've wondered why this job pays so well," he continued. "Why someone working in an ordinary forecourt shop earns nearly twice the usual local rate. Now you know. You're not shop assistants. You're guards. Protectors. The last line of defence between our world and what lies beyond."

Another crash sounded, closer this time.

Elias tensed, his tall form abruptly alert.

"They're testing the customer-toilet door," he said, barely above a whisper.

Graham nodded. "They'll try the cleaning cupboard next, then the ceiling tiles. They're becoming more inventive."

"How long will this last?" Niamh asked, gripping her device tightly.

"Until dawn," Graham replied. "The barrier strengthens in daylight."

I thought of Molly and Ben sleeping safely at home and Mrs Ahmed next door, keeping watch over them. I thought of everyone in Ravensbrook who had no idea what happened at Blackthorn each night.

"If we fail..." I said slowly.

"If they break through, they won't stop at the station," Graham confirmed. "They'll spread through Ravensbrook first, then farther afield."

A terrible ripping noise came from beyond the stockroom door, like fabric being torn on an immense scale. Elias moved away from the door and positioned himself between us and whatever approached.

"The ceiling," he said. "They're crossing through the ceiling."

Graham stood, his expression grim.

"This is where you make your choice, Sarah. Niamh. You can leave now. Elias can take you safely through the warded staff exit and escort you to your cars. Or you can stay and fight. But if you leave, don't come back. We'll find others."

I looked down at the engraved device in my hand, then across at Niamh. Her face was pale but determined.

"I'm staying," she said firmly.

I thought about my children again, about the world they lived in and the future they deserved. If these things crossed, what sort of world would Molly and Ben inherit?

"I'm staying too," I said.

Graham nodded, and something like pride showed in his eyes.

"Good. Remember your training. Remember the rules. They exist for a reason."

The ceiling in the main shop collapsed with a tremendous crash. Inhuman screams filled the air, accompanied by the stench of rotting vegetation and scorched wiring.

"They're through," Elias said, moving towards the door.

Graham handed each of us a battery storm lamp with an amber filter.

"Stay together. Aim at their centres, and whatever you do, don't look directly into their eyes."

Elias opened the door onto the chaos beyond.

The shop I knew had become a battlefield. Shadowy figures moved through the darkness, their forms changing and twisting as if they could not decide what to be. The ceiling had split open, revealing not the night sky but something else: a depthless darkness that hurt my eyes.

I raised my inspection-torch device, remembering everything I had learnt from Graham's folder. The entities could not hold their shapes in our reality without attaching themselves to an anchor - an object, an animal or a person. If we struck their centres before they anchored, the warding force would drive them back.

For the next several hours, we fought.

Elias was swift and silent, reinforcing the torn boundary and intercepting the largest entities before they could emerge fully. But the attack came from too many directions for him to contain alone. Graham directed us with the calm authority of someone who had endured this many times before.

Niamh and I worked together, watching each other's backs and using the engraved devices to repel anything that drew too close. Beams of hard amber-white light struck the entities at their centres and folded their shifting bodies inwards, forcing them back into the ruptures before they could seize a person, a fallen display or even one of the dead insects scattered beneath the light fittings.

It was terrifying. It was exhausting. Somehow, we held.

At approximately 05:45, pale dawn reached the jagged edges of the damaged roof. The entities began to retreat.

The tears in reality narrowed, and the impossible darkness beyond them faded. One by one, the shadowy forms recoiled from the daylight and slipped back through the closing breaches.

By 06:00, it was over.

The shop was wrecked. Glass covered the floor. Shelving lay overturned, and stock was scattered everywhere. The ceiling and roof had been torn open, but the breach had been stopped.

Graham surveyed the damage.

"Could have been worse," he said. "Much worse."

Niamh sat on the floor with her back against the counter, shocked but alive.

Elias had disappeared, as he often did when the danger passed. Only a lingering chill and the smell of rain suggested he had ever been there.

"What happens now?" I asked, my voice hoarse from shouting warnings throughout the night.

"Now," Graham said, almost smiling, "you go home to your children. You rest. Then you come back for the 22:00 shift. My crew will have the station restored before then."

"Just like that?" Niamh asked incredulously. "We nearly died, and we simply come back for another shift?"

"That's the job," Graham said. "That's what you chose."

I helped Niamh to her feet. We were both filthy and covered in a substance I did not want to identify, but we were alive.

"I need to ring home," I said. "I need to check on Molly and Ben."

Graham nodded.

"Use my office. The phones in there are still working."

As Niamh and I made our way to the office, picking carefully through the wreckage of the forecourt shop, I felt something I had not expected.

Pride.

We had faced the worst the other side could throw at us, and we had survived. More than that, we had protected not only ourselves, but everyone beyond the station.

I rang Mrs Ahmed. She told me Molly and Ben were fine, still sleeping peacefully. They had no idea what their mother had just endured, or what she had fought to keep from reaching them.

That was exactly how it should be.

When I put down the phone, I looked at Niamh.

"Are you all right?"

She nodded slowly. "I think so. It is just a lot to take in."

"It gets easier," I said, though I was not entirely sure that was true. "And it is important. What we do here matters."

"I know," she said. "I just never thought I would be guarding a doorway between worlds when I applied for a job in a petrol-station shop."

I almost laughed at the absurdity of it. "The benefits are good, though."

"True," she agreed, a small smile breaking through her exhaustion.

We left Graham's office and found him already directing a clean-up crew that seemed to have appeared from nowhere. Men and women in plain dark overalls worked with practised efficiency, clearing debris, replacing shattered fittings and restoring the shop to its ordinary appearance.

"Go home," Graham told us. "Be back for the 22:00 shift. It will all be ready by then."

As we walked across the forecourt towards our cars, the morning sun warming our faces, I realised that my job had changed completely. I was no longer merely a forecourt-shop assistant earning good money. I was someone who protected our world from the terrible things trying to force their way into it.

For Molly and Ben, I would do it.

I would return night after night, follow the rules and keep the boundary secure. I could not bear to imagine what might happen if I did not.

I got into my car and saw Niamh doing the same. We would both come back that night, ready for another shift and ready to keep the darkness on the other side.

This was our choice now.

This was our job.