Miles Logan(Martin Lawrence) is a jewel thief. Things go awry while he's stealing a huge diamond in downtown L.A.: a thief, Deacon(Peter Greene), tries a double-cross, the police arrive, and Miles is arrested, but not before he hides the jewel in an air duct of a building under construction. Two years' later, he's out of prison and he heads for the site: it's L.A.'s new police headquarters! Posing as a reassigned cop, Miles gets into the building, but before he can recover the swag, he's partnered with a naive detective and sent out to investigate burglaries. With Deacon on his trail, he must recover the diamond, keep the cops fooled, and do a few good deeds as a detective who can think like a criminal.