The film revolves around the lovely girl, Regan MacNeil, who lives with her mother - an actress named Chris MacNeil. Suddenly one day, Regan changes strangely from Regan's face to her voice and accompany with some stranger abilities. Despite using multiple therapies, hospitals and doctors could not figure out etiology of syndromes that Regan is suffering from. Suspect that Regan is possessed , Chris has invited two pastors. However, things are not simple like that...