She had lived beside him for four months and had never once seen his face. She knew him instead the way you know weather: through a wall of old plaster that carried his radio's low jazz at seven, the particular late hour his shower ran, and — whenever her own music went past midnight — two knuckles of sound, patient, never angry, asking her to turn it down.
She was thirty-one, four months into a lease she'd signed without a second name on it, and worked hours that brought her home when the rest of the building was asleep — the only reason, she suspected, she'd learned him so well and seen him so little.
Tonight the record kept turning past one because she wanted it to. His two knocks arrived on schedule, and instead of lifting the needle she crossed to the wall and knocked back — twice, then a third, testing whether he'd hear a question in it.
He did. A long quiet followed, long enough that she thought she'd overplayed a code neither of them had ever agreed they were speaking, and then two knocks came back, higher up the wall, unmistakably an answer.
She was in the hallway in a borrowed sweatshirt before she'd decided to be, and his door opened before her hand reached it, like he'd been standing just as close on his side of that same distance.
His flat ran the same shape as hers, reversed, so that walking through it felt like walking through her own apartment reflected in a window at night — the life next door she'd been half living for months with no face on it.
His bed stood against the wall her headboard backed onto, the one piece of furniture in the building she could have drawn from memory without ever having entered the room.
She crossed to it and laid her palm flat against the plaster on his side, the exact place — she was almost sure — where her own headboard knocked in her sleep, four inches of lath and horsehair the only thing that had ever separated them.
He came and stood close enough that she felt him before he touched her, and said the one rule a month of knocking had never needed spoken aloud until now: "Knock if you want me to stop."
She kept her palm flat on the wall, on his side of it now, and didn't knock.