In the dead of this frozen apocalypse, the shelter's fusion core was on the verge of overload.

I grabbed my repair kit and sprinted for the basement, only to have the guard captain's girlfriend, Miranda Dunn, step right into my path.

"Everyone, come look! Zach’s about to dump poison into the vents. He's gonna kill us all!"

Her voice cut through the air as she shrieked.

"I didn’t approve a private room for him two days ago, and now, he wants us all dead!"

The guards didn't bother asking questions. They slammed me hard against the freezing metal door.

"Zach, are you going to kill us all over a room? We're taking you in for interrogation!"

I stared at the control panel, its readings spiking into the red, and shouted, "If the core blows up, none of us will make it out alive!"

But they were too busy trying to impress Miranda and brushed off my warning, thinking I had lost it.

Nineteen minutes remained before the core exploded.

Red lights strobed wildly across the shelter, the alarm blaring so loudly that it seemed to drill straight into my skull.

I didn't even bother wiping the sweat off my face. I just ran, hauling my heavy precision welding kit down the hallway toward the heart of the entire shelter: the fusion core.

If it blew, all 30 thousand people here would turn into frozen statues in an instant.

Outside, the temperature sat at -112 degrees. Without the core's heat, no one would last ten minutes.

I was almost at the basement entrance when a woman in a fur coat suddenly stepped out and blocked me.

She was Miranda Dunn, the mistress of Leon Garrett, the guard captain.

In a world where even potatoes were rationed, she still had flawless makeup on.

"Stop right there, Zach! What are you sneaking around with?"

She spread her arms and blocked my path, her eyes sharp and suspicious.

"Move! The core's about to blow. I need to get in there and fix it!" My throat felt raw as I tried to push past her.

Miranda shoved me hard. I stumbled into the wall, and the repair case slammed to the floor with a heavy crash.

"Fix it? Looks more like you're planning to poison us!"

She raised her voice, the sound echoing harshly through the corridor.

"Everyone, come look! Zach's about to dump poison into the vents! I didn't approve a private room for him two days ago, and now he wants us all dead!"

The alarm had already drawn a crowd. Panicked residents filled the hallway. At her shout, dozens of eyes snapped toward me.

"Miranda, have you lost it?" I snapped. "That's liquid metal repair compound, not poison!"

I scrambled up, reaching for the case on the ground.

"Don't move! Hands up!"

A squad of fully armed guards rushed in, led by Leon. He strode over and pulled Miranda into his arms, his gaze turning cold as he looked at me.

"Zach. What do you think you're doing?"

"Captain Garrett, the core pressure's at critical. If we don't fix it now, it'll be too late!"

I pointed at the flashing red numbers on the wall, my voice shaking.

Miranda clung to him, pointing at my case as she shrieked, "He's lying! He said it himself. He wants revenge. He's going to dump poison into the cooling system! He's just bitter I wouldn't give him a private room. Someone like him would do anything!"

Leon let out a cold scoff and waved his hand.

"Hold him down. Search the case."

Two large guards lunged forward and pinned me, slamming my face against the freezing metal door. My glasses hit the floor and shattered under Leon's boot.

"Leon! Look at the panel! That's a core overload warning!"

I struggled, my cheek scraping against the metal until I felt skin break.

Leon flipped open my case and stared at the canisters of silver liquid inside.

"What is this? No labels. Looks like some kind of toxic chemical to me."

He picked one up, like he was about to smash it on the ground.

"Don't! That's high-purity nano repair compound. There are only three cans left in the entire shelter!"

My vision went red.

If the core melted down without it, nothing could save us!

"Zach, you're quite the actor."

Miranda walked over and drove the heel of her shoe straight down onto the back of my hand.

"You're just a grease monkey. What makes you think you're some kind of savior? Leon, don't waste time talking to him. Lock him in solitary. We'll deal with him after the alarm stops."

I looked at the timer on the wall. Seventeen minutes left before the core blew.

"If the core blows up, none of us will make it out alive!" I shouted at Leon, spit hitting his boots.

Leon wiped his boots off with a look of disgust and slapped me across the face.

"The shelter doesn't depend on one mechanic. Cole is already on his way." He turned to his guards. "Take him."

They dragged me down the hall like I was a pile of trash.

People lined the corridor, pointing at me. Someone even spat in my direction.

"Disgusting! I can't believe he tried to kill us for a room."

"I used to think Zach was a decent guy. Guess you never really know someone."

I watched in despair as the steel door to the core section slipped farther and farther away.

The red glow from inside had already flooded half the hallway.

-

The solitary room was cold and damp, lit by a single dim bulb.

They cuffed my hands behind the chair. I sat there, burning with urgency.

Time kept slipping away, second by second.

I looked up at the vent in the ceiling. The vibrations coming through it were getting stronger.

That was the core, crying out.

The door opened. Miranda stepped in in her high heels, calm and composed. She held a half-eaten chocolate bar in her hand, one of the shelter's restricted supplies.

"Not feeling so great now, huh?"

She leaned against the table, looking at me in contempt.

I forced myself to stay calm and met her eyes.

"Miranda, what do you want? What do you gain by stopping me from fixing the core?"

She took another bite of chocolate, smiling as if she had already won.

"What do I gain? Plenty."

She leaned in closer, lowering her voice.

"All the scarce supplies in the core district warehouse are under my name now. If you went in there and saw half the antibiotics and canned food missing, how do you think I'd explain that?"

My whole body went rigid. I stared at her, stunned. "Are you out of your mind? You stole strategic reserves?"

"Stole?" Miranda let out a cold laugh. "Leon runs the guard. What he says goes in this shelter."

She tossed the chocolate wrapper onto my face.

"Cole is an old fool. He won't dig into anything. He just follows procedures. Once he lowers the pressure, I'll fix the records. No one will ever know."

"He can't lower it!" I shouted, panic breaking through. "The pressure spike is from thermal backflow. You have to seal the cracks with nano repair compound! If he tries to vent it, the core will blow instantly!"

Miranda curled her lip, unimpressed.

"Stop trying to scare me. You think I don't get it? You just want credit. You want that private room. Zach, as long as I'm here, you're never getting anywhere."

Right then, the entire room jolted hard. The light overhead swung violently, dust shaking loose from the ceiling.

Miranda screamed, nearly losing her balance.

That was the sound of a partial collapse.

"What was that? Didn't they say Cole was already there?"

Her face went pale, a flicker of panic breaking through.

I slammed my body against the chair, desperate.

"He messed up! He must've opened the secondary pressure release valve! Quick, take me to the comms room. I need to guide him. If that valve doesn't get shut, we're done!"

Miranda steadied herself. Her eyes flickered, then hardened into something colder. She walked to the corner and yanked the internal comm line straight out of the wall.

"Guide him? Sounds more like you want to trigger the explosion remotely. Zach, a terrorist like you doesn't get to talk."

She dropped the severed wire, turned, and ran out, locking the door behind her.

"Miranda!" I roared. "Get back here! You're gonna kill everyone!"

I shouted until my throat tore raw, but the only thing that answered me was dead silence.

The clock on the wall ticked on.

Eight minutes left until the expected explosion.

Heat began to rise through the floor beneath my feet. The energy from below was already pushing through the insulation.

I stared at the cuffs around my wrists and pulled with everything I had.

Skin split. Blood ran down into my sleeves.

I couldn't feel the pain anymore, just a hollow, sinking dread.

Were 30 thousand people really about to die because of one selfish woman?

Suddenly, a deafening blast tore up from deep underground.

The steel door of the cell warped, the walls cracking open with jagged splits. A wave of scorching air surged down the corridor.

The impact threw me off the chair, dragging it down with me as I hit the ground.

Boom!

Then came the chain of explosions, one after another.

Screams echoed through the structure. People crying, shouting, the sound of debris crashing down.

The east sector of the shelter was gone.

Not long after, the cell door was forced open.

Several guards, covered in dust and soot, rushed in and hauled me to my feet without a word.

"Move. Commander Norris wants to see you."

By the time they dragged me into the central plaza, it had already turned into a wreck.

The air reeked of burning and blood.

On the giant screen, Miranda was somehow still in the safe zone, recording a message.

Tears streamed down her face as she spoke to the camera.

"Don't be scared, everyone. We've already secured the poisoner, Zach. The core is damaged, but Captain Garrett will protect everyone."

I stared at her face, sick with anger, wishing I could tear that act apart.

Shelter commander, Russell Norris, stood in the middle of the plaza, his face pale, his body trembling slightly.

Beside him, Leon was speaking in a low voice, reporting.

"Commander Norris, this is all Zach's doing! He broke into the core sector and poisoned it, triggering the explosion."

Leon pointed straight at me, his voice sharp with intent.

Russell turned, his deep-set eyes locking onto mine. "Zach, what do you have to say?"

I hadn't even opened my mouth before Leon drove a kick into my stomach. "Talk. Where did you hide the rest of the poison? You got accomplices?"

Pain folded me over. I gasped for air.

"Commander Norris… The explosion…was caused by Cole's mistake… Miranda stopped me from fixing it…"

"Stop lying!" Miranda rushed forward from nowhere, pointing at me as she shouted. "You're insane! You're about to die, and you're still trying to drag me down with you? Commander Norris, don't listen to him. He's a killer!"

Russell ignored her. His gaze shifted past us, landing on a pile of rubble nearby.

A strip of red fabric stuck out from beneath it.

His personal guard captain ran over, picking it up, his voice breaking.

"Commander Norris… This belongs to Ms. Cheryl… She was touring the core sector… We can't find her."

Russell's body swayed.

Cheryl Norris was his only granddaughter.

"Don't stop looking! Find her!"

His roar cut across the entire plaza.

Seeing that, Leon immediately drew his pistol and aimed it at my head.

"Commander Norris, this animal got Ms. Cheryl killed. I'll take him out right now and make him pay with his life!"

His finger trembled on the trigger.

I knew why. He was afraid of the truth coming out.

The crowd around us started shouting along.

"Kill the murderer!"

"Kill him! Make him pay for the family members we lost!"

I looked at their furious faces, and all I felt was cold, empty despair. They had no idea the real killer was standing right in front of them, taking credit.

Just as Leon was about to pull the trigger, Russell spoke.

"Wait."

He stepped toward me, slow and deliberate, his eyes colder than ice.

"Zach, I'll ask you one more time. Why did the core explode?"