One. Two. Three. Are you ready to play?

Ever since Kaye's grandfather died, she's been obsessed with counting things: the steps to her bedroom, the dolls on her sister's bed, even the threads on her favorite blanket. It's arithmomania, and with the selective mutism that sometimes prevents her from speaking, she literally can't find the words to talk about how she feels now that Grampa is gone.

When they take the summer to clean out and renovate his old house, Kaye finds herself counting the days. That is, until her younger sister, Holly, starts finding dolls. She finds them buried in the backyard, stuffed in the walls, crammed into the closets. From the first one, Kaye knows they aren't like normal dolls. They smile at her like they know something, and sometimes their eyes open and close on their own.

Kaye hears her sister talking to them constantly—and she swears she's heard the dolls whispering back. Everyone assumes that Holly's just a kid with a good imagination. Kaye doesn't think it's a game, because she knows that Holly—and the dolls—are going to make her play with them. Forever.