The classroom smelled like chalk dust and cheap air freshener. Sunlight filtered lazily through blinds, catching motes that floated like tiny sparks over open notebooks. Students murmured, tapping pens, flipping pages—mundane, harmless things. You were scribbling in the corner, headphones tucked behind your ears, the scratch of your pen the only real sound you noticed.

Park Sunghoon sat across the aisle, arms folded, watching the teacher drone on. His expression was neutral, almost bored, like he was watching a slow, predictable movie he didn’t care to enjoy. But beneath the calm, there was something sharp, calculating. Like he could see through walls, through desks, through the thin masks everyone wore.

Then it started.

A scream—not the shrill, immediate panic of a fire drill, but the wet, desperate kind that makes you freeze mid-breath.

The girl in front of you doubled over, clutching her throat. Blood speckled her uniform, bright against the pale fabric. Her eyes were wide, pupils blown, frantic. Around her, chaos ignited. Chairs toppled. Pens scattered. Students shouted, but nothing made sense.

Sunghoon didn’t move at first. Not a muscle. He tilted his head, assessing, cataloguing, like a predator noting a flaw in its prey. Then he slid his notebook closed and leaned back, expression calm, almost bored.

You froze, staring, chest tightening. “W-what—”

“Don’t.” His voice was quiet, deceptively soft, cutting through the hysteria like glass. “Don’t scream. Don’t run blindly. Watch first. Think later.”

Your pen clattered to the floor. The girl—she was on the ground now, convulsing, her classmates recoiling in a mix of horror and disbelief. Blood pooled quickly around her hands. Her screams became guttural, inhuman. The first transformation. The first death.

Somewhere behind the panic, a door slammed. Windows rattled. The school—your safe, predictable, ordinary school—shifted. Something in the air changed, thick and electric, full of fear and the smell of iron.

Sunghoon stood slowly. His movements measured. He stepped over desks without touching them, eyes flicking from one potential threat to another. He didn’t panic. He didn’t hesitate. The others were screaming, crying, running, but Sunghoon—he was already three steps ahead. Already calculating the angle of escape, the path of attack, the only rule that mattered: survive.

“Everyone’s about to make a mistake,” he said softly, almost to himself. But you heard. And it made your stomach knot. “And I’m not one of them.”

The first bite happened then. Right behind the girl, someone else fell, convulsing violently, eyes gone. The sickening sound of bone snapping, teeth tearing—it should have been unbearable, but your brain registered it with detached horror, like reading a case study you’d rather not touch.

Sunghoon’s gaze flicked to you once. Calm. Assessing. He didn’t reach out. Didn’t warn you. He just knew. And that knowledge made your chest tighten more than the screams ever could.

By the time the teacher tried to intervene, it was too late. The infection had already begun its slow, inevitable ripple. Students screamed, scrambled, some tripped over others in frantic panic.

Sunghoon moved through it with calm precision, weaving between the chaos. But even he couldn’t dodge everything. A hand grabbed his arm from behind—another student, frantic, thrashing—and he stumbled slightly. A sharp, guttural sound made him pause. The infection was spreading too fast, too unpredictably.

He blinked, scanning, calculating, but for the first time, uncertainty flickered in his eyes. A scream tore through the classroom, close, raw—and Sunghoon realized: he wasn’t untouchable. Not today.

His lips tightened. “Then…” he murmured, almost to himself, “I adapt.”

Even as the room descended into madness, Sunghoon’s calm remained, but the truth settled like a weight: the rules had changed. No one was safe. And he had just learned, the hard way, that cleverness alone wouldn’t be enough.