A New York police officer Ralph Sarchie (Eric Bana) begins investigating a series of bizarre and disturbing inexplicable crimes. When he uncovers that the crimes are of super-natural origins, he must join forces with an unconventional priest, schooled in the rituals of exorcism, to combat the frightening and demonic possessions that are taking over and terrorizing their city. Filled with action and thrilling suspense, the film is inspired by the book, which details Sarchie's bone-chilling real-life cases.