Kevin Costner is Mr. Brooks, a psychopathic serial-killer and family man, who's content to run his box factory and murder people until Dane Cook discovers his secret, all the while ducking Demi Moore, an independently wealthy cop who hunts them both. Kevin Costner a serial killer? Dane Cook in a drama? Demi Moore in a movie? Go ahead, pinch yourself, I'll wait.
Mr. Brooks is a family man; a devoted husband, business man of the year, and father of a college-age daughter. He likes pottery. He makes boxes. He murders couples having sex and gets off on it. He likes coffee. He talks to an imaginary friend (William Hurt), his psychopathic alter-ego and partner in crime.
Dane Cook is an engineer who takes naughty pictures and catches Mr. Brooks in the act one night. Rather than go to the police, he decides to confront the psychopathic killer and blackmail him into taking him (Cook) along on a murder. For some reason, Brooks (Costner) agrees and immediately begins plotting Cook's death.
Meanwhile, a totally improbable cop (Demi Moore), who's worth over $60 million thanks to her dad, makes catching them her sole priority in life. The chase is on.