The Brubaker house always smells like other people's dinners. Mara has babysat three-year-old Theo eleven times now. Same rules every time: monitor on, door cracked, bed by eight. It's 9:40 and the living room is dark except for the little green screen. Theo is a small white smudge, asleep on his side. Then the screen hisses with static, and when it clears, the smudge is sitting straight up, facing the camera.

Mara taps the screen, sure it glitched. Just a shadow, a trick of the night-light. She flips the monitor over to check the battery, and when she turns it back, Theo is lying down again, perfectly normal. She lets out a breath. Probably nothing. She sits back on the couch with her phone.

Mara scrolls her phone and tries to forget the screen. But the room has gone cold, and the green light from the monitor flickers on the wall. She doesn't want to look at it again. Slowly she realizes the humming is no longer coming from the speaker. It's coming from the top of the stairs, and it's getting closer.

Mara turns toward the stairs. A small figure in pajamas stands at the top in the dark, humming. It's Theo, but his feet aren't touching the floor. He drifts down one step, then another. 'You always come,' he says in a voice far too old for him. 'That's why I picked this house.' She backs to the front door, but it won't open.