The entrance to the 1988 Olympic Maintenance Tunnel was not marked on any modern GPS, nor was it visible from the sleek, glass-and-steel skyline of the New Seoul. It was buried beneath a layer of decades-old industrial neglect in the Gimpo district, hidden behind a rusted perimeter fence and a thicket of invasive locust trees that had clawed their way through the asphalt.
Han-su killed the engine.
The silence that followed was physical. It pressed against his eardrums like deep-sea water. For hours, the rhythmic thrum of the diesel engine had been their heartbeat, the only thing separating them from the static, dead world outside. Now, there was only the sound of the rain—a relentless, rhythmic drumming on the truck's thin aluminum roof—and the shallow, jagged breathing of fourteen people trapped in a metal box.
"We're here," Mrs. Cho whispered. She was huddled in her sodden mink coat, her eyes fixed on a concrete bulkhead that looked more like a tomb than a tunnel entrance. "The 'Iron Gate of the Han.' They built it during the Cold War paranoia. It was supposed to be a way to move supplies if the bridges were blown by the North. Then they forgot about it. Capitalism prefers bridges; they're easier to tax."
Han-su climbed out of the driver's seat. His legs felt like they were made of rusted clockwork. Every joint popped and groaned. He looked at his hands in the dim light of the overhead moon—they were stained with grease, gasoline, and the dried, greyish ichor of the thing he had killed on the highway. He didn't recognize them anymore. These weren't the hands of a man who delivered high-end electronics; these were the hands of a scavenger.
"Min-ah, Ji-young. With me," Han-su commanded.
He didn't ask Mr. Kim. The man was slumped over the steering wheel, his eyes vacant, staring at a family photo he'd pulled from his wallet. Kim was still physically present, but mentally, he was sliding into the "Grey Zone"—that state of shock where a survivor simply stops perceiving reality to protect what's left of their sanity.
The three of them stepped into the mud. The air here smelled of wet earth and ancient, stagnant water. Han-su carried the heavy crate of industrial thermite, while Min-ah held her pike and Ji-young carried the LED lantern, its beam cutting a weak, yellow path through the fog.
They reached the door. It was a massive slab of reinforced steel, ten inches thick, held shut by a series of industrial locking bolts that had rusted into a single, fused mass of iron.
"The thermite," Han-su said, setting the crate down. "We need to melt the hinges and the primary bolt. If we just try to blow it, the shockwave will collapse the ceiling of the entrance. We need surgical heat."
He opened the canister of grey powder. It looked innocent—like ash. But he knew that when ignited with the magnesium strips, it would reach temperatures exceeding 2,500°C. It would turn the steel into a liquid waterfall.
"Ji-young, take the lantern and walk twenty paces back. Watch the tree line," Han-su instructed. "The light from this is going to be visible for miles. It'll be like a flare in a dark room. Anything with eyes within three wards is going to see us."
Ji-young nodded, her face pale but her grip on the lantern steady. She moved back, her boots squelching in the muck. She was learning the most important lesson of the new world: Don't ask 'why,' just ask 'how much time do I have?'
Han-su began to prep the door. He packed the thermite powder into the crevices of the hinges, using duct tape to hold the volatile mixture in place. His fingers were shaking. Not from fear, but from the sheer weight of the responsibility. If this didn't work, they were trapped in a cul-de-sac with a truck full of crying children and a horde of "Runners" somewhere behind them.
"You're thinking too much," Min-ah said. She was standing guard, her back to the door, her eyes scanning the dark woods. "I can hear your brain grinding from here."
"I'm thinking about the math," Han-su muttered, stripping a magnesium fuse. "Fourteen people. Three liters of water left per person. Two days of food. If this tunnel is flooded or blocked halfway through, we don't have the calories to turn back and find another way."
"Then don't turn back," Min-ah said simply. "Survival isn't about having a Plan B. It's about making Plan A work until you die."
Han-su looked at her. Her face was a mask of cold resolve. She had lost her entire volleyball team in the first three hours of the outbreak—trapped in a locker room with one girl who had "turned" silently. She didn't talk about it, but the way she gripped her pike told the story.
"Stand back," Han-su warned.
He struck a flint against the magnesium. A spark jumped. The strip hissed, glowing with a blinding, white-blue intensity. Han-su turned and ran toward Ji-young, diving behind a concrete pillar just as the thermite ignited.
The night exploded.
It wasn't a bang, but a roar—the sound of the atmosphere itself being scorched. A pillar of white fire erupted against the steel door. The darkness of the Gimpo district was incinerated by a light so bright it cast long, sharp shadows of the skeletal trees against the clouds. Inside the truck, the children shrieked, thinking the world was ending again.
Through his squinted eyes, Han-su saw the steel begin to glow. First a dull cherry red, then a vibrant orange, and finally a brilliant, liquid white. The rust vanished instantly. The hinges, forged to last a century, simply ceased to be solid. They dripped onto the wet ground, hissing as they turned the mud into steam.
The light lasted for nearly a minute. When it finally died down, the world felt even darker than before. The "purple spots" in Han-su's vision made it hard to see, but the smell told him everything. The scent of molten iron—sweet, metallic, and hot.
"It's done," Han-su wheezed, his lungs burning from the chemical fumes.
He walked toward the door. It was sagging now, held only by the friction of the frame. He signaled to the truck. "Kim! Reverse the truck! Hook the winch to the handle!"
Mr. Kim snapped out of his trance. He backed the truck up, the engine growling. They hooked a heavy steel cable to the red-hot handle of the door.
"Pull!"
The truck strained. The tires chewed into the mud, throwing up clumps of earth and grass. The cable went taut—twang—vibrating like a guitar string. For a second, it felt like the door would hold. Then, with a scream of tortured metal that sounded like a dying giant, the door gave way.
It fell outward, slamming into the mud with a sound that shook the earth.
Beyond the door lay a throat of blackness. A perfectly circular concrete tunnel, sloping downward at a steep angle. The air that rushed out was freezing, smelling of salt and ancient dampness. It was the breath of the river.
"Get the truck inside," Han-su ordered. "Min-ah, help me clear the debris. We have to get that door back up—or at least block the entrance—before the guests arrive."
But it was too late.
From the woods, a sound rose. It started as a single, high-pitched howl, then was joined by dozens of others. It wasn't the dogs. It wasn't the "Runners." It was something else—the "Strays" from the treatment plant had followed the light.
Han-su saw the beams of multiple flashlights bouncing through the trees. They were coming fast, and they were on foot.
"Kim! Inside! Now!"
The truck lurched into the tunnel, its headlights finally cutting through the gloom. The interior of the tunnel was ribbed with concrete arches, covered in a thick layer of black slime.
Han-su and Min-ah scrambled inside just as a gunshot rang out. The bullet sparked off the concrete rim of the entrance.
"They're here!" Ji-young screamed, hauling the last of the children into the back of the truck.
Han-su didn't have time to close the door—it weighed tons and the hinges were gone. He looked at the crate of packages. He grabbed two more smoke canisters and a roll of duct tape.
"Kim, drive! Don't stop until I tell you!"
The truck began its descent into the bowels of the earth. As they moved deeper, the temperature plummeted. The headlights revealed the walls were weeping water—the weight of the Han River was pressing down on them from above, held back by three feet of aging concrete.
Han-su stood at the back of the moving truck, looking out at the receding rectangle of the entrance. He saw the silhouettes of the "Strays" standing at the mouth of the tunnel. They didn't follow. They stood there, their flashlights illuminating the falling rain.
"Why aren't they coming in?" Min-ah asked, her pike leveled at the darkness.
"They know something we don't," Mrs. Cho whispered from the corner. She was clutching her birdcage. Jjizzeu, the canary, had started to flutter frantically against the wire bars.
The bird wasn't singing. It was screaming.
Han-su looked down at the floor of the tunnel. In the reflection of the truck's taillights, he saw that the water wasn't just dripping from the ceiling. It was rising from the floor.
They weren't just in a tunnel. They were in a drain.
"Kim, floor it!" Han-su yelled.
But the truck was already slowing down. The tires weren't gripping anymore. They were sloshing.
"Han-su..." Ji-young's voice was small, filled with a new kind of terror. "The walls. Look at the walls."
Han-su turned the lantern toward the concrete.
The walls weren't covered in slime. They were covered in hair.
Thousands of "Sleepers" had crawled into this tunnel years ago—perhaps during a previous flood or a smaller, forgotten outbreak. They had been trapped here in the dark, their bodies fusing together in the dampness. They weren't dead. They were hibernating. And the heat from the thermite, combined with the vibration of the truck, was waking them up.
A hand—long, grey, and tipped with nails that had grown into claws—reached out from the "slime" and gripped the side of the truck. Then another. Then a hundred more.
The tunnel didn't lead to the coast. It was a digestive tract.
"Don't stop," Han-su whispered, grabbing the frying pan with a knuckles-white grip. "Kim, if you stop, we're the first meal this tunnel has had in twenty years."
The truck pushed deeper into the dark, the sound of the engine echoing like a heartbeat in a throat. The journey of life and death through ruined world had just truly begun, and the first mile was through the stomach of the city.
Survival Status: Volume 2, Part 4
Environment: Subterranean Maintenance Tunnel (Flooding).
Immediate Threat: The "Wall-Crawlers" (Dormant Infected).
Mental State: Han-su (Hyper-Focused), Ji-young (Alert), Mr. Kim (Catatonic).