Thirty-five minutes before the weekend.
Inside Classroom 2-A, time had stopped flowing—dragged forcibly into a crawl by the stale heat of a Friday afternoon and the dying whir of the ceiling fan. Late summer sunlight baked the windowpanes, printing long shadows of aluminum frames across rows of desks covered in carved initials and pen-scrawled nonsense.
Of the thirty students in that room, Yoon Jaeho knew precisely which five still had their souls present. The rest had already left—wandering the shopping streets of Hongdae in their heads, or slipping into the screens of online games.
Jaeho stood at the front, his back to the desks. His right hand moved without pause, cutting logarithmic equations into the faded green surface of the chalkboard.
Tap. Tap. Tap.
The rhythm of chalk against board was the only thing keeping this class from collapsing entirely into entropy. For most teachers, the last period on a Friday was a form of institutional punishment. For Jaeho, it was an anchor point. Among these rows of numbers and variables, in this eight-by-eight-meter room, the world finally made sense. Every problem had a formula, and every question a definitive answer. Here, his existence carried an absolute function.
Jaeho glanced toward the middle row without slowing his hand.
Kim Minjae, third seat from the front, had surrendered entirely to gravity. His head rested on folded arms, shoulders rising and falling in the heavy rhythm of profound exhaustion. Jaeho let him be. Minjae had finished a night shift at his uncle's convenience store at four in the morning. Waking him now would produce nothing but empty eyes.
In the left corner, Lee Sora sat with a posture held upright only through sheer force of will. Her left hand pressed quietly against her lower abdomen at intervals. Sora's name had been absent from the lunch attendance list. Her weekly allowance had likely gone to her younger sibling's workbooks again. Jaeho filed a mental note: a melon bread and a carton of milk on her desk before cleaning rotation.
His gaze moved to the far back, near the rear door with its rusted hinge.
Park Jihoon. The boy had walked in twenty minutes ago, uniform wrinkled, sweat still damp along his hairline. He was hunched over his desk, his right hand gripping a pen like a last weapon. Jihoon's eyes darted in small, panicked arcs between the half-erased board and his notebook.
Seeing that contained panic, Jaeho didn't turn around. He didn't tell the boy to calm down.
For a moment, the pen in Jihoon's grip looked exactly like the one Jaeho had held at seventeen — white-knuckled over an exam paper, certain that falling behind meant falling entirely. He knew that specific shape of panic. He had worn it for two years before anyone noticed.
He turned back to the board.
And he deliberately changed the rhythm of his chalk strokes. He stretched the pause between equations, stepping back from the board to give the world an extra thirty seconds—just so a seventeen-year-old boy wouldn't feel judged by his inability to keep up.
To Jaeho, being a good teacher wasn't about shouting until they listened. It was about listening to what they never said aloud.
Bzzzt.
A brief vibration in his slacks broke the manufactured silence.
Jaeho set the chalk in the tray, dusted the white powder from his fingertips, and reached into his pocket. He glanced at the lit screen.
Choi Seungwoon:
Working late again?
Jaeho held back a smile. His childhood best friend had an internal radar that activated precisely whenever Jaeho arrived at the most tedious point in his routine.
Choi Seungwoon:
How long are you going to be the poorest teacher in Seoul.
To anyone else, it was a corporate heir mocking a friend's mediocre life. But Jaeho knew how Seungwoon translated feelings. Poorest teacher in Seoul wasn't a jab at his bank account. It was Seungwoon's way of asking: When are you going to stop running yourself dry for other people's children?
Jaeho didn't bother typing a defense.
Yoon Jaeho:
[Thumbs up emoji]
Across the city, in a premium downtown office, Seungwoon was likely staring at the screen with a flat expression. The man whose life consisted of bespoke suits and profit margins would never truly understand the stale air of Classroom 2-A.
His reply came instantly.
Choi Seungwoon:
[Nausea emoji]
Click.
The classroom went dark.
The hallway outside was already emptying. Pairs of shoes squeaking against linoleum, voices dropping as they hit the stairwell, the specific Friday-afternoon current of thirty bodies evacuating toward the weekend. Jaeho moved against it — slower, unhurried, the chalk dust still faintly present at the back of his throat.
At the top of the stairs he paused. The main road would be gridlocked by now. Shoulders pressing into shoulders, the accumulated heat of rush hour — a weight he didn't have the reserves for tonight.
The shortcut, then.
Take the shortcut tonight, he thought, sliding the door shut behind him.
He didn't know this decision was the exact moment his normal life ended. A trivial choice to avoid a traffic jam, about to burn his quiet routine entirely to ash.