Newlyweds Parker and Madeline move into their dream home. As they settle in, they discover a box of old love letters written to the original owner. And as the couple digs into the increasingly obsessive correspondence, a mysterious woman arrives with a horrifying secret that threatens their lives.

On the day of his scheduled execution, a convicted serial killer gets a psychiatric evaluation during which he claims he is a demon, and further claims that before their time is over, the psychiatrist will commit three murders of his own.