The halls of 12 Grimmauld Place had always seemed like they breathed—like the house itself listened.

You’d never been here before, not properly. Sirius always said it was cursed. Rotten. A mausoleum for pure-blood pride and Black family secrets. So when he finally got the chance—his parents out visiting the Malfoys—he insisted on dragging you, James, Remus, and a few others here for a night of rebellion.

It was all mischief at first: firewhisky Sirius snuck from the cabinet, music playing way too loud for a house with this much dust in its bones, James dramatically reenacting a Quidditch match in the drawing room, Remus laughing harder than he had in weeks.

But you were tired. Or maybe just… unsettled.

There was something about this house that got under your skin.

Or maybe it was him.

Regulus Black.

Same year. Different worlds. Slytherin. Pure-blood heir. Quiet as a shadow, sharp as a razor. You’d never spoken much. But there were moments. Always in Potions, where your fingers sometimes reached for the same beaker. Or in the library, when he’d look up from his book a half-second before you did. Or in the Great Hall, where your eyes met across the tables like a question left unspoken.

Sirius loathed him. Spat his name like poison.

But you… didn’t. Couldn’t.

And now, you were here. In his house.

Everyone else was asleep, or pretending to be. Sirius had passed out with his boots still on. You, on the other hand, had slipped off to the bathroom with a headache and a heart pounding for reasons you couldn’t name.

The mirror was fogged from the hot water. You were halfway through washing your hands when—

CRACK.

You yelped.

Kreacher.

That miserable, matted creature had appeared without warning. Before you could speak, he seized your wrist with bony fingers and muttered something about “Master Regulus requests her presence”—and then, with a pop, he dragged you out of the bathroom and into a room.

The air was colder here.

You blinked, heart racing, suddenly facing a dark bedroom lit only by a few floating candles and the distant moonlight through velvet curtains.

And there he was.

Regulus.

Sitting on the edge of the bed, shirt slightly wrinkled, dark hair falling into his eyes. A book half-open beside him. He hadn’t moved.

His gaze lifted slowly to meet yours.