In the 1950s and 1960s, the panicked girl Christine (Amber Heard) ran in the wilderness. She set fire to the nearby farmhouse, but was eventually caught by the police and sent to the North Bay Mental Hospital. Because Christine was extremely aggressive, she was placed in a special ward, where her freedom was restricted. In addition to the cold doctors and nurses, she could see the girls next door, Emily (Mamie Gummer), Zoe (Laura-Leigh), Iris (Lyndsy Fonseca) and others. From the girls, Christine learned that the mysterious Dr. Stringer (Jared Harris) seemed to have been doing some experiments on the girls. At the same time, it seemed that there was a terrifying evil spirit roaming in the mental hospital, ready to take the girls' lives at any time...