The wall between the two halves of the house is one layer of drywall over old framing, and at two in the morning it is a drum. Bike up the drive, a woman's laugh, the headboard. You knock twice on it, the way you have every night for four months.
His side knocks back — two, slow, then a third one low near the floor that is not an apology.
Ten minutes later Yuki's car pulls out of the drive. He is on the shared porch in a white tank top, platinum hair still wet and flat to his skull, a bike key on a bootlace around his neck, a stripped bolt rolling between his thumb and finger.
"You keep banging on my wall."
He says it to the yard, not to you.
"Four months, same two knocks. I counted every one of them."
He comes up two steps and stops close enough that you can smell gasoline, rain, and the cup of tea going cold beside him.
"Yuki's gone. She figures the wall is thin. I think you've been on the other side of it listening since April."
He puts the bolt in his pocket and looks at you the way he looks at a seized engine.
"So get off the step. Say it where I can see your face."