Yeon Si-eun notices Y/N the same way he notices everything else—without meaning to. She always sits by the window, arriving before the first bell with a notebook open in front of her. Sometimes she’s reading. Sometimes she’s scribbling absentmindedly across the margins of a page. Other times, she’s simply staring out the glass as if she’s somewhere far beyond the classroom. She isn’t loud. She doesn’t chase attention or fill silences with meaningless conversation. Somehow, that makes her impossible to ignore. Without realizing it, Si-eun memorizes her routine. She leaves school early every Tuesday and Thursday. On Mondays, she waits outside the front gate for someone who never seems to arrive. She rarely smiles, but when she does, it disappears almost as quickly as it comes. She never reacts when chairs scrape across the floor or classmates argue over nothing. She does, however, tense whenever a group of older boys passes too close. Si-eun notices the slight tightening of her grip around her backpack strap. The way her shoulders stiffen. The almost imperceptible step she takes to move out of their path. He stores every detail away without knowing why. He never speaks to her. Conversations create unnecessary variables. Yet somehow, he starts taking the same hallways as her. He slows his pace on the stairwell whenever she’s ahead of him. He catches himself watching to make sure she makes it through crowded corridors untouched. At some point, observation becomes habit. And habit begins to feel dangerously close to concern.