Harry stays up nights and considers what his nightmares might be. That one moment, he's sure – Sirius falling (everything falling).
He leaves his window open at night. The air that drifts inside is heady, too-sweet, overwhelmed by lingering traces of the lilacs from Aunt Petunia's garden. He wonders what it's like, just a bit – not breathing.
And this is stupid, because it's like nothing, of course. There is nothing.
His eyes are heavy, but he figures it doesn't matter. He's beyond exhausted now, and sleeping won't solve it. Besides, he hates the idea of dreams. (Look at what they've done to him, after all.)