The day their father killed their mother, sisters Victoria and Lilly vanished near their suburban neighborhood. For five long years, their Uncle Lucas (Nikolaj Coster-Waldau) and his girlfriend, Annabel (Jessica Chastain), have been madly searching for them. But when, incredibly, the kids are found alive in a decrepit cabin, the couple wonders if the girls are the only guests they have welcomed into their home. As Annabel tries to introduce the children to a normal life, she grows convinced of an evil presence in their house.

Are the sisters experiencing traumatic stress, or is a ghost coming to visit them? How did the broken girls survive those years all by themselves? As she answers these disturbing questions, the new mother will find that the whispers she hears at bedtime are coming from the lips of a deadly presence.