Set in 1990, Joe 'Deke' Deacon (Denzel Washington) is a burnt-out deputy from Kern County, CA, who left working the spotlight of high-profile cases five years ago for quieter pastures, sacrificing the spotlight and his family in the process. Rami Malek is Jim Baxter, a hotshot homicide detective for the Los Angeles County Sheriff's Department on top of the case to catch a serial killer brutally slaughtering young women. Deke has a knack for visualizing crime scenes and cracking cases by observing 'the little things' - the seemingly unimportant clues that lead a serial killer to be caught.  However, his reputation of following his own guidelines rather than the law has earned him a reputation, especially as events of his past have haunted him to ruin.

Deke travels to LA to deliver evidence for a case from Bakersfield but finds himself drawn into doing additional legwork off the clock because of the similarities between the current murders and one he had been working on back when he was last in Los Angeles that precipitated his exile. The arrogant Baxter initially dismisses Deacon as a loose cannon distraction, but eventually finds there's a method to his madness that could be an asset to cracking the case. Their clues eventually lead to appliance deliverer Albert Sparma (Jared Leto), though they aren't quite sure if he did the deeds or if he's merely drawn close to the case because he is a fanatic for serial-killer crimes and intrigued at being thought of as a suspect. However, the demons that plague Deke seem to be infecting Baxter as he too begins to obsess about the case. John Lee Hancock writes and directs.