When he opened his eyes, there was no ceiling.
To be precise, there was a ceiling. A slab of concrete lay wedged diagonally overhead, and the sky was visible through the gap. A hazy gray sky. Something that might have been clouds—or dust—hung low overhead.
“...What the hell?”
Han Donghoon tried to sit up and slammed his elbow into a rebar rod lodged in his side. A curse escaped him. It hurt. If this was a dream, it shouldn't hurt this much.
Where am I?
He looked around. It was a studio apartment. No—it had been a studio apartment. One entire wall had collapsed, and the sink was overturned. The refrigerator had fallen on its side, lying on the floor with the door hanging open. There was nothing inside.
Donghoon looked down at himself.
He wasn't wearing his military uniform. He had on a hoodie and sweatpants. The clothes he'd put on after coming home from his military discharge. Right. He'd been discharged a week ago. He'd cooked ramen last night, watched YouTube, and fallen asleep.
“What the...”
He looked outside.
The road had split open. The asphalt had surged upward and hardened like waves, while the buildings were either half-collapsed or reduced to bare frames. A traffic light had bent and been driven into the ground. One car had crashed into a utility pole. The driver's door stood open, but there was no one inside.
There were no people.
Not a single one.
Donghoon held his breath as he peered outside through the collapsed wall. There was no sound. No cars, no voices, not even a dog barking. Only the wind rumbled softly. That wind carried a strange smell. Not burning, not rot—something difficult to describe. Like the taste left on the tip of your tongue after licking metal, mixed into the air.
“Let's get out first.”
Donghoon looked for his shoes. One sneaker was wedged beneath the sink, and the other was near the entrance. The front door had twisted together with its frame and wouldn't open. He'd have to leave through the collapsed wall.
As he climbed over the concrete debris, Donghoon thought. An earthquake? An earthquake this severe in Korea? Or a war? If a war had started one week after his military discharge, the timing was seriously fucked.
Once he got outside, he saw the scale of it.
It wasn't just one block. As far as he could see, everything looked like this. Apartment complexes had toppled like dominoes, while the commercial buildings were nothing but bare frames, like cages with all their glass shattered. The sky was still gray, and he couldn't tell where the sun was. Yet it wasn't dark. A hazy light spread evenly in every direction.
Donghoon searched his pockets. He had his phone. The screen was cracked, but it still powered on. The time display was strange. There was no date, and the time was locked at 00:00. Naturally, there was no signal.
“Fuck.”
Donghoon put the phone back in his pocket and started walking.
He needed to find water. Food after that. Then a weapon. The order came to him automatically. Some of it came from what he'd learned in the military, but it was more than that—a habit ingrained in him long before.
Donghoon had been a strange kid since childhood. He enjoyed watching disaster documentaries, read survival manuals, and searched for wilderness survival videos instead of camping trips. While his friends played games or soccer, Donghoon stayed home practicing how to tie knots. Whenever people asked him why, he never had an answer. It was just fun. He enjoyed imagining how he would survive if the world collapsed. To be honest, it wasn't merely fun. It thrilled him. There had even been times when he'd seriously thought, I want to live in a world like that. Of course, he'd never told anyone.
That was why he'd adapted well in the military, too. He was good at shooting and marching. He just couldn't adapt around people. He was quiet, expressionless, and often heard that no one could tell what he was thinking. His seniors left him alone. There was no point bothering him when he never reacted. His juniors were afraid of him. He'd never done anything to scare them, though.
It was the same after his military discharge. He was comfortable being alone at home. His parents had divorced and lived separately, and Donghoon lived alone in a studio apartment under his father's name. He'd spent the past week without deciding what to do before returning to school. Cook ramen, watch YouTube, sleep. That was all.
That life had suddenly become this.
Donghoon looked for a convenience store. The sign had fallen off, but he could still recognize the structure. The glass door was shattered, so he simply walked in. Shelves had toppled over, and snack bags and drink cans were scattered across the floor. Donghoon grabbed water first. Four 500-milliliter bottles. Two in his pockets, two in his hands. Then he picked up a few energy bars and tucked them inside his hoodie.
That's when he heard it.
A scraping sound. Like fingernails dragging across concrete. No—something harder than fingernails scraping across the floor.
Donghoon stopped.
The sound was coming from the back of the convenience store. The storage room. Its door was half open.
Donghoon backed away without a sound. His heart began to race. He'd fired plenty of rounds in the military, but he'd never seen real combat. Donghoon knew training and actual combat were different. He'd seen it hundreds of times in survival videos. In a real situation, your hands trembled. Your judgment slowed. So you had to move instead of stopping to think.
Donghoon left the convenience store.
He didn't run. Running made noise. He walked quickly, checking behind him. Something was moving inside the convenience store. It was too dark to make out its shape, but it wasn't human. Humans didn't move like that. It looked like it was crawling on all fours—or maybe standing on two legs with its upper body bent forward at an extreme angle.
Donghoon entered an alley. A narrow alley. The building walls on either side limited his view, but on the other hand, anything coming from behind could only approach through the narrow passage. A choke point. A concept he'd learned in the military surfaced automatically.
He stopped at the end of the alley and looked back. Nothing had followed him. Donghoon let out a breath.
“What the hell was that?”
His heart was still racing. His hands trembled. Donghoon repeatedly clenched and opened his fists as he steadied his breathing.
An animal? A dog? No. Dogs didn't move like that. And it was too big to be a dog. It was human-sized. No—slightly larger than a human.
Donghoon took a sip of water and started walking again.
He needed to get somewhere high. Somewhere he could see his surroundings. Donghoon found a building that looked relatively intact. A five-story commercial building. Cracks ran along the exterior walls, but the structure was holding. An emergency staircase was attached to the outside. Donghoon climbed it.
The sight from the rooftop left Donghoon speechless.
The entire city was dead. All the buildings, as far as the distant mountain ridges, had either collapsed or tilted. Cars had been abandoned across the roads, and smoke was rising somewhere in the distance. And then.
There was something in the sky.
Something enormous floated between the clouds. At first, he thought it was part of the clouds. But the clouds moved, and it didn't. Black. Neither round nor square, but irregularly shaped. It looked like a hole had been punched in the sky.
Donghoon stared up at it for a long time.
“...A rift?”
The word slipped from his mouth. Donghoon himself didn't know why it had occurred to him. No—he did know. He'd seen it somewhere before. That thing.
In the military.
Donghoon had read a novel in the military. Someone had left a printed web novel on top of a locker in the barracks. He couldn't remember the title. There was no cover or title page. It was just a stack of A4 sheets densely packed with the body text. Donghoon had read it because he had nothing else to do. He'd finished the entire thing. Then he read it again. He took it out whenever he was bored. From his assignment to his military discharge, those printouts had been Donghoon's only entertainment. Secretly, he'd found it fun. The story of a protagonist surviving alone in a ruined world suited Donghoon perfectly.
As Donghoon looked up at the black hole in the sky, he recalled the novel's opening scene.
“On the day of the ruin, a rift opened in the sky. A black hole. Something like a wound embedded between the clouds. Three hours after it opened, the first monster descended to the ground.”
A chill ran down Donghoon's back.
It was identical.
That thing in the sky was exactly like the rift described in the novel. Irregularly shaped, black, fixed between the clouds and utterly motionless.
It could be a coincidence. No—it had to be a coincidence. A novel was a novel. It was a story someone had made up. Reality couldn't be the same as a novel.
But what about what he'd seen in the convenience store?
A shape that seemed to crawl on all fours. Human-sized. Moving in a way no human could.
The weakest monsters in the novel were called Crawlers. They moved on all fours, relied on hearing more than sight, and weren't much of a threat alone—but became dangerous in groups. They responded to sound. That was why you couldn't run.
Donghoon hadn't run from the convenience store. On instinct. No, not instinct—because he'd read that novel. The memory that he mustn't make a sound had remained somewhere in his body.
“No way.”
Donghoon sank onto the rooftop floor.
It made no sense. Had he entered the world of the novel? That sort of thing only happened in fiction. But if this place wasn't the world of the novel, how else could he explain the situation?
A ruined city. A rift in the sky. Monsters of unknown origin.
Everything lined up.
Donghoon clutched his head. Confusion came before fear. When people were thrown into a situation they couldn't understand, the first thing they felt wasn't fear but confusion. Fear came after they understood the situation.
And Donghoon was beginning to understand.
He recalled the novel's contents piece by piece. Three hours after the rift opened, the first monster descended. For the next twenty-four hours, only low-level monsters appeared. That was the only preparation time given to the survivors. In the novel, those twenty-four hours were called the “grace period.”
He didn't know whether they were inside or outside the grace period. But if what he'd seen at the convenience store was a Crawler, that meant the higher-level monsters hadn't descended yet. He had time.
Donghoon stood up.
He remembered what the protagonist had done first in the novel. Secure a base. A middle floor, not underground. If it was too high, escape would be difficult; if it was too low, monsters could get inside. Somewhere between the third and fifth floors. A structure where the stairs could be blocked. Fewer windows.
Donghoon looked over the building he was standing in. A five-story commercial building. There was one exterior emergency staircase. He'd have to check the interior stairs. The first three floors appeared to be shops, while the fourth and fifth were offices.
Not bad.
Donghoon thought as he came down from the rooftop. He remembered the novel in its entirety. He'd taken it out whenever he was bored, from his assignment until his military discharge. He'd read it dozens of times. Not just the broad strokes—even the details remained clear.
The survival sections were especially vivid. Donghoon had liked those parts. He skimmed the rest, but he read the survival sections carefully.
He entered the fourth floor. There were two offices. One door was locked, and the other was open. He entered the open one. Four desks, chairs, filing cabinets, and a water cooler. There was still water in the cooler. Two windows. One was broken, and the other was intact. He blocked the broken one with a filing cabinet. It was heavy, but he could push it.
He closed the door and pushed a desk in front of it.
Donghoon sat on the floor and took another sip of water.
It was quiet. So quiet he could hear his own heartbeat.
Donghoon closed his eyes.
The world of a novel. It was ridiculous. But if he denied it because it made no sense, he'd die. Accepting reality came first. Whatever the situation was, what he had to do now remained the same.
Survive.
Donghoon opened his eyes.
Strangely, the word settled his mind a little. Survive. It was what Donghoon had imagined all his life. How would he survive if the world collapsed? He'd spent decades preparing for the answer to that question. Of course, he'd never actually believed the world would end. And honestly, it wasn't all fear. Somewhere inside, he was excited. He knew it made him a freak. But it was the truth.
Donghoon pulled an energy bar from his pocket and tore it open.
As he chewed, he thought. In the novel, the Howler appeared when the grace period ended. One rank above the Crawler. It stood on two legs, was fast, and called its companions by screaming. Once one of those things appeared, it was hard to hold out alone.
He needed to find a weapon before then.
Donghoon finished the energy bar and stood up.
In the novel, the protagonist grew stronger each time he killed a monster. He'd started as an ordinary human, but after killing several Crawlers, he began to change. He grew faster, stronger, and his senses sharpened. There was no status window or anything like that. His body simply changed. One day, he realized he was different. And once he surpassed a certain level, he was supposed to unlock a unique special ability. If he grew even stronger, an ultimate skill. The protagonist of the novel had achieved all of it.
Donghoon looked down at his hands. They were ordinary hands. Other than a few calluses from the military, there was nothing special about them.
Could he kill that monster with these hands? If he killed one, would he change too?
He didn't know. A novel was a novel, and he wasn't even sure this was really the world of that novel. Only one thing was certain. Those monsters were real, and without a weapon, he would die.
Donghoon left the office and went down the stairs. One of the shops on the third floor was a hardware store. The shutter was halfway down, but he could crawl underneath it.
Inside, he picked up a hammer. It was heavy. Then a box cutter. It was small, but better than nothing. There was rope, too. He took a bundle.
Donghoon gripped the hammer and felt its weight.
Could he fight that monster with this? In the novel, a Crawler's weak point was the back of its neck. Its hard outer shell was thinner only there. Would striking it with a hammer work?
He'd never tried it. Obviously.
Donghoon left the hardware store and went back up to the fourth floor. He closed the door, pushed the desk in front of it, and sat on the floor.
The sun was setting. The gray sky was growing darker. Night was coming.
Night was dangerous in the novel. The monsters became more active. Crawlers, in particular, were nocturnal. The one he'd seen at the convenience store had probably still been half-asleep. Once night fell, it would start moving in earnest.
Donghoon rested the hammer across his knees.
He couldn't sleep. At least not tonight.
Darkness descended. The streetlights, naturally, didn't come on. The entire city sank into darkness. Donghoon peered outside through the gap in the window.
He heard something.
From far away. The sound of multiple feet scraping across the ground. It wasn't just one. Three, four, five... He gave up counting. There were many.
And amid those sounds, he heard another noise, low and drawn out.
A howl.
It wasn't a human cry. It wasn't an animal's howl, either. Somewhere in between. It sounded sad, almost hungry. Just hearing it sent a chill down his spine.
Donghoon gripped the hammer tighter.
“The grace period is coming to an end.”
A line from the novel surfaced in his mind.
“When the grace period ends, true hell begins.”
Donghoon opened his eyes wide in the darkness.
Fine. Hell or whatever.
Surviving was what Donghoon had always loved most.