A year after a home invasion left her traumatized, Cecelia and her family move into a new house with a complex security system that is supposed to make her feel safe. But reality proves different as strange things begin to happen and the security system reveals that the house had a prior occupant: Lydia. On her quest to discover the fate of Lydia, Cecelia uncovers metaphorical skeletons in the closet, and she realizes that no one's secrets are safe -- including her own.