A loving couple learn that their two adopted nieces have brought a dark secret into their home in this foreboding domestic thriller from executive producer Guillermo del Toro (Pan's Labyrinth), and director Andy Muschietti. Victoria and Lilly were just little girls when their father murdered their mother. In the aftermath of that tragedy, both girls disappeared without a trace. Desperate, their Uncle Lucas (Nikolaj Coster-Waldau) and his girlfriend Annabel (Jessica Chastain) searched everywhere for the missing girls. Five years later, Victoria and Lilly are both found living in a derelict cabin deep in the woods. Incredibly, they've managed to survive on their own, though years of isolation have left them both in a feral state, and unable to communicate. Without hesitation, Lucas and Annabel welcome the two frightened girls into their home, and work hard to make them feel comfortable. But when a series of ominous events lead Lucas and Annabel to suspect that Victoria and Lilly share ties to an evil beyond human comprehension, the couple must discern whether the two young girls are merely dealing with the emotional aftershocks of a life-altering tragedy, or have attracted a force that could destroy their family all over again.