After her parents' painful divorce, Evie Archer hopes that moving to Ravenglass, Massachusetts, is the fresh start her family needs. But Evie quickly realises that her new home - known by locals as the Horror House - carries its own dark past after learning about Holly Hobbie, who mysteriously vanished from her bedroom one night. But traces of Holly linger in the Horror House and slowly begin to take over Evie's life.

A strange shadow follows her everywhere she goes, and Evie starts to lose sight of what's real and what isn't the more she learns about The Lost Girl. Can Evie find out what happened the night of Holly's disappearance? Or is history doomed to repeat itself in the Horror House?