Seoul arranged itself in two faces.
The first face bathed in neon light and the roar of engines. The second was the dead spaces between all that brightness.
The alley behind the school was one of those dead spaces.
The transition was immediate the moment Yoon Jaeho stepped past the mouth of the alley. The blaring of horns from the main road cut off, replaced by the low hum of an old electrical transformer in the brick wall. The corridor was less than two meters wide. Four-story walls rose on either side, sealing out the afternoon light and trapping a permanent dampness.
Jaeho pushed both hands into his trouser pockets. The air here was five degrees colder than the main street.
He fitted his wireless headphones over his ears. A slow-tempo jazz instrumental flowed in, drowning the lingering noise of Class 2-A.
His shoes struck the wet asphalt. His feet knew this alley better than his mind did.
The lengthwise crack in the asphalt at the fourth meter — the one he always stepped around without thinking. The rusted pipe along the left wall that dripped at the exact same point every day, something he had long since stopped noticing. The cardboard in the right-hand corner, wet or dry depending on the weather. He had never seen who left it there, but it had become a reliable distance marker.
This alley wasn't a route home. It was two minutes between two worlds — just long enough to clear Class 2-A from his head before he reached the station.
He had been doing this since his second year of teaching.
Tap. Tap. Tap. A steady rhythm, bouncing between the narrow walls. The exact same cadence as chalk against his chalkboard.
A sharp smell bit at his nose—wet moss, rusted pipes, stagnant drain water. At the midpoint of the alley, the single street lamp flickered in its death throes, then went out entirely. Darkness moved in immediately. The silhouettes of trash cans and soggy cardboard dissolved into the color of night.
Jaeho kept his pace. Then the anomaly arrived.
The air around him thickened. Grafity tilted, The weight of Jaeho's own body doubled, pressing down through his spine.
The jazz in his ears lost its bass. The notes flattened out, leaving only a high-pitched static hiss that stabbed at his eardrums.
Jaeho stopped.
Silence ambushed him. The alley had erased Seoul entirely.
His rational brain scrambled for explanations. Exhaustion. Low blood pressure. Two nights of inadequate sleep.
Jaeho exhaled slowly. Cold air left his mouth and formed a thin mist.
The mist did not dissipate. Instead of rising, the white vapor drifted backward—pulled unnaturally toward the deepest shadow of the dead end. At the tip of his shoes, the surface of the murky puddle began to vibrate in rapid, concentric circles.
His hands gripped the cloth inside his pockets. His right foot lifted.
One step.
Two steps.
Compressed air detonated against his back.
Jaeho's shoulder blades cracked, the sound sharp enough to be heard. Both knees met the asphalt. The sound of wet fracture echoed hard, but his brain refused to process the pain. His face hit a murky puddle.
His lungs thrashed. Every breath demanded air that wasn't there. All that entered his throat was the smell of rust.
The world contracted to a radius of half a meter. His hearing went dead—replaced by a constant screaming static that drove every other frequency out of the alley. Black spots crawled wild from the corners of his eyes, consuming what little light remained.
In pure biological panic, the last of his adrenaline forced his neck to turn. His cheek dragged across rough asphalt.
At the far end of the alley, through eyes that were already beginning to fail, he saw a darkness that had swallowed the night's own color. Beside it, a dense mass was boiling the empty space around itself.
The sound of fabric tearing rippled through the puddles beneath his face.
Crack.
A brick wall in the distance collapsed in slow motion. Glass came down and became heavy snowfall.
The boiling mass was forced backward. It stopped. Then it looked down.
No readable facial structure. But Jaeho understood with certainty that he was being looked at.
A person stepping on a dry twig does not crouch down to consider what they've snapped. The shadow cast its gaze downward. Scanning the pile of organic matter on the asphalt. Broken, inanimate debris left behind by something stepped on.
The next second, the suffocating pressure broke.
They were gone.
Car horns from the main road struck Jaeho's eardrums. The transformer hum came back on. Seoul breathed again.
But for the body lying on the asphalt, time had stopped running.
The nerves in his extremities dimmed, leaving a numbness that kept rising. The murky puddle beneath his cheek slowly warmed, fed by something thick and iron-smelling that kept seeping out and spreading across one side of his face.
His last breath trembled. A blood bubble formed at the corner of his lips—then burst.
The black spots in his eyes merged. And consumed everything.