At 3:07 a.m., someone knocks. It sounds like the person you would give anything to save.Nora Whitlock, a divorced hospice nurse, inherits her late grandmother's crumbling farmhouse in Pellam Hollow, Maine. There is one condition: she must sleep there for three nights. Inside the pantry door, written in black marker, are five rules. The first is the most important: Never answer the knocking. Not once. Not for anyone.On the first night, her nine-year-old daughter's voice calls from the porch while Junie lies asleep beside her. On the second, it is the voice of her brother Eli, missing for two years, begging her not to lock him out. She never picked up his last call. She would give anything to answer this one.Then Nora finds her grandmother's ledger. Fifty-one years of nights, each ending in the same word: Held. On the final page, in her grandmother's own handwriting, are tomorrow's names. The last one is Junie's.The whole village sleeps because this one house stays shut. But the keeper is dead, the door is cracking, and the thing outside has already learned how Nora's family sounds.Some doors keep monsters out. Some were built to keep a promise in.