After a young student at St. Mark's Catholic School for Girls suddenly disappears, the school is closed and abandoned. But after 13 years, the school is reopened as a "boot camp for the soul." Now more prison than school, 5 new wayward students rebel against Father Drake (Ron Perlman) and the headmistress Miss Pearce (Amy Ciupak Lalonde). When the group of girls realize they possess supernatural skills, they don't hesitate to use them to try and escape. After all of their attempts fail, they realize that they must unite their skills and powers to face the malevolent entity, Legion, who holds thrall over the institution in a battle for their lives and their souls...