A dying prisoner, a former hit man, confesses to Cannon that he killed Frank's wife and child 14 years ago when Cannon was a cop. Cannon investigates to find the person responsible while trying to control his desire for revenge.
Cannon turns down a client, and when she is killed in her house shortly after his visit, he is drawn into both her murder investigation and the reason she called him.
When the son of a famous actress disappears the police think its another instance of his recurring drug problem. Cannon is hired to find him, but no one is telling him the whole truth.
Frank Cannon and Barnaby Jones investigate the rape and murder of a young lawyer who was about to blow the whistle on her corporate employer. But they're investigating for different clients and from different angles.
A doctor treats a diabetic in the emergency room and she then dies. He claims that the patient was wearing an indicator bracelet that has seemed to have vanished. Cannon is hired to investigate.
Cannon and a female vice squad officer who's on leave after being viciously beaten while undercover posing as a prostitute go after this same man who has previously beaten prostitutes to death while playing the music "The Wedding March".
Cannon is hired by an insurance company representative to investigate a fatal automobile accident, but nothing about the accident is as it seems . . . and neither is the insurance company representative.