In an alternate worldone ravaged by centuries of war between man and vampires, a legendary Warrior Priest (Paul Bettany) from the last Vampire War now lives in obscurity among the other downtrodden human inhabitants in walled-in dystopian cities ruled by the Church. When his niece (Lily Collins) is abducted by a murderous pack of vampires, Priest breaks his sacred vows to venture out on an obsessive quest to find her before they turn her into one of them. He is joined on his crusade by his niece's boyfriend (Cam Gigandet), a trigger-fingered young wasteland sheriff, and a former Warrior Priestess (Maggie Q) who possesses otherworldly fighting skills.