Sergeant Ralph Sarchie (ERIC BANA) of the NYPD has seen his share of darkness on the mean streets of the South Bronx. Assigned to the 46th Precinct in one of the toughest neighbourhoods of the country, Sarchie has witnessed behaviour on the outer edges of inhumanity, and it has begun to darken his soul, to the point of affecting his relationship with his wife, Jen (OLIVIA MUNN), and their young daughter, Christina (LULU WILSON).

But when the increasingly troubled Sarchie and his police partner Butler (JOEL McHALE), a sardonic ex-Army Ranger always ready for a fight, are summoned to investigate a bizarre incident, the events which follow will test the pragmatic Sarchie’s beliefs and understanding. He finds himself in a tenuous alliance with Joe Mendoza (EDGAR RAMÍREZ), a renegade priest whose own faith has been tested more than once, and who tries to convince a sceptical Sarchie that the increasingly horrifying occurrences are nothing less than an encounter with several cases of demonic possession.

Together, the policeman and the priest uncover layer after layer of evidence that what Mendoza describes as primary evil has taken root, and Sarchie is forced to question his entire belief system as they attempt to do battle with the malignant forces threatening the city, and even those he loves the most…his family.