It's 1:47am when he hears the door.

Not her door — the stairwell door, two floors down, which means she took the stairs again. He's noticed she does this when she's had a long shift. He doesn't examine how he knows the difference.

Renji is at his kitchen window with a cigarette, not particularly doing anything. The city is laid out below in the way Tokyo arranges itself at 2am — still lit, still moving, entirely indifferent. He finds this restful. He has never needed the city to care about him.

He hears her footsteps on the stairs.

Third floor. Fourth.

The stairwell door opens.

He takes a drag and doesn't turn around.

He can track her exactly without looking — the particular drag of her steps when she's tired, the fumble of keys that means her hands are full, the small sound she makes under her breath when the lock sticks, which it does on cold nights, which she hasn't learned to account for yet because she's only been here a month. He has catalogued all of this without meaning to, the way he catalogues everything in his immediate environment, because his immediate environment has historically been the kind that punishes inattention.

That's what he tells himself.

Her door opens. Closes.

The light comes on under her door. He can see the thin line of it from his side of the hall.

He finishes the cigarette.

Renji Kuroda is not, by nature, a man who notices people. He moves through the world with the detachment of someone who learned early that caring about outcomes makes you slower and slower gets you dead. He is very good at not noticing people. He has been, in the one month since she moved into 4A, completely unable to apply this skill to her.

It started with a Tuesday morning. She was leaving for campus at the same time he was coming back from something he won't name, still in last night's clothes, and she looked up at him with the unguarded expression of someone who hasn't learned to be careful around him yet and said good morning like it was the most natural thing in the world. He said nothing. She smiled anyway and went down the stairs.

He stood in the hallway longer than he'd like to admit.

It's gotten worse since. He knows her schedule now — classes until late on Tuesdays and Thursdays, part time shift somewhere on weekends, convenience store runs at odd hours when the deadline has gone too long and she needs something that isn't whatever is in her fridge. He knows she's a student. He knows she's young — young enough that the gap between her life and his is almost absurd, almost offensive, the kind of distance that shouldn't need explaining.

He knows she has no idea what he is.

This is the only argument he has left for the distance he's maintaining. She says good morning and he gives her the minimum and goes back inside and that is the correct arrangement because she is twenty-something and exhausted and writing papers at midnight and she deserves a building where the neighbour across the hall is simply a neighbour.

He is not simply a neighbour.

Someone in the organisation has noticed him noticing her. It was mentioned once, casually, in the way that things are mentioned casually that are not casual at all. He said nothing and changed the subject and came home and stood at this window for a long time.

Across the hall, her light is still on.

1:52am. She has an early class tomorrow. He knows this.

He lights another cigarette and looks at the city and does not look at the line of light under her door.

He looks at the line of light under her door.