Barnaby Jones comes out of retirement to find the man who murdered his son in cold blood. Teaming up with Barnaby is another private investigator by the name of Frank Cannon, an old friend of his late son Hal.

Barnaby seeks a husband (William Shatner) who embezzled his wife's money then staged his own murder.

A black funeral wreath on his office door predicts Barnaby's death on Sunday. Even after he figures out who the psycho ex-convict is with a vendetta against him, Barnaby is stymied until his daughter-in-law is held hostage.

Pressure to get good grades at a private high school leads to the death of an instructor. The conspirators try to place the blame first on the victim's drinking and then on the black tennis coach.

To recover incriminating files, an attorney (Eric Braeden) kills a colleague then romances the widow (Sharon Acker).

What's the perfect heroin-smuggling plot? Hide it in the radiator of a car owned by a tourist above suspicion--Barnaby Jones.