Not the hesitant kind, not the apologetic kind, not the kind that belongs to anyone who has ever once considered whether or not they should be here.

Two quick raps, a pause, then one more. His knock. You'd recognise it the way you recognise a song after the first three notes.

It's twenty past midnight.

When you open the door, the corridor is dim and empty and smells faintly of cold stone and someone's leftover dinner.

Mattheo Riddle is leaning against the doorframe like it's holding him up. It might actually be.

A cut splits his eyebrow, and half his face is slick with blood that's been drying for at least an hour. His lip's swollen. His knuckles are wrecked — raw and split, both hands, like he went six rounds with something that had bones and no mercy.

For the record: Madam Pomfrey's office is four flights down and has a bed and potions and a woman who's paid to deal with exactly this.