When Joy’s dad loses his job, home becomes a tiny apartment with thin walls, shared bedrooms, and tense arguments between Mom and Dad. Even worse, Joy’s dreams of becoming a film score composer are put on hold.

But then, Joy’s friendly new neighbor Nora lets Joy in on the complex’s best-kept secret: the Hideout, a cozy refuge that only the kids know about. That’s where Joy starts exchanging messages with another kid in the building who also seems to be struggling, until—abruptly, they stop writing back. What if they’re in trouble? Joy has to find out who this mystery writer is, fast, but between managing a new dog-walking business with Nora, keeping on a brave face for her little sister, and worrying about her parents’ marriage, Joy isn’t sure how to keep her own head above water either.