Fletch is a fish out of water in small-town Louisiana, where he's checking out a tumbledown mansion he's inherited. When a woman he flirts with turns up dead, he becomes a suspect and must find the killer and clear his name.
Tony Costas, a brash, obnoxious, sexist and racist Detroit cop who has long since stopped following the rules, gets told that he will have to work with Inspector Fuji, a straightlaced policeman from Japan. Fuji is in Detroit searching for a Japanese engineer who has gone to America with plans for a top secret car part. The pair naturally fail to get along at first, but as the investigation continues, they almost begin to come close to tolerating each other's presence.
Bumbling Ernest P. Worrell is assigned to jury duty, where a crooked lawyer notices a resemblance with crime boss Mr. Nash, and arranges a switch. Nash assumes Ernest's job as a bank employee, while Ernest undergoes Nash's sentence to the electric chair. But instead of killing him, the electrocution gives Ernest superhuman powers, enabling him to escape from jail and foil Nash's attempt to rob the bank.
Fletcher Reede is a fast-talking attorney and habitual liar. When his son Max blows out the candles on his fifth birthday he has just one wish - that his dad will stop lying for 24 hours. When Max's wish comes true, Fletcher discovers that his mouth has suddenly become his biggest liability.