They know who you are. They know where to find you. And if you get in their way, there's nothing between heaven and earth that can save you. Police psychiatrist Cal Jamison (Martin Sheen) is plunged into a demonic nightmare when he finds detective Tom Lopez (Jimmy Smits) next to the body of a ritually sacrificed child. Though Lopez is branded the prime suspect in a string of similar murders, Cal is not convinced of his guilt and begins a relentless search for the truth. Soon Cal's investigation makes him a believer in the supernatural – and the target of a terrifying conspiracy.