Frank Cannon is a tough, middle-aged, portly ex-cop turned private eye. A gourmet, with expensive tastes, he mostly took cases at a substantial fee so he could afford indulging in personal luxuries. He was a shrewd investigator, dedicated, clever and despite his bulk, was not afraid of getting physical if he had to.
Cannon investigates the death of two women who were connected to a faith healer who preaches to his flock that modern medicine is the work of Satan. A young man with a brain tumor may be the next victim.
Cannon investigates on the behalf of a oil executive who claims he is being framed for fraud and embezzlement. But he runs into heavy resistance in his investigation from the corporations domineering female president.
A contractor refuses to pay bribes, and is accused of plotting a political asassination.
A mobster hires Cannon to find out who tried to kill his ex-wife in a failed hit attempt. But Cannon suspects the mobster himself may be the actual target after another attempt is made on him and not his ex-wife.
A girl's suspicious death brings Cannon to Texas.
A well-to-do young man's death in Acapulco is ruled an accident, but his family hires Cannon to investigate.
A policeman injured in a payroll robbery asks Cannon for help.
A young prisoner is forced to do the bidding of a gang boss.
A Dutch Nazi-hunter is on the trail of an SS man.
Mike Tampa owns a vineyard in northern California... his land alone is worth $2 million, but he loves wine-making and is not considering selling. His father started the vineyards, handed them down to him, and he hopes that his son Johnny Tampa will be the third generation. Mike Tampa, however, has been the victim of three murder attemptsâ€”in the last one, his brakes were tampered with, and he barely survived when he took his car down a mountain road. At this point, his secretary calls on Cannonâ€”secretly, because the stubborn Mike has refused to do anything. Cannon is brought in to investigate. We learn that Johnny Tampa had only been re-united with Mike two years ago... after not having seen him for 20 years (Mike and his wife went through a bitter divorce 22 years prior and she took their son down to San Francisco). Cannon suspects that Johnny may be pulling a con and that he is not really Mike's son. The winery accountant says that they had Johnny checked out by a PI down in SF n
Cannon reopens the case of an old shooting.
A general wants Cannon to find the daughter he put up for adoption years before, but there is opposition to the search.
Cannon reluctantly takes the case of a disappearing bridegroom, but it's more than it appears.
A torpedo plays dead to testify, but the mob sniffs him out.
A released prisoner disappears en route.
Palestinian terroists kidnap an Italian industrialist's daughter to free a jailed comrade.
An old friend hires Cannon to bring back the body of his dead son from Mexico and to find his killer. Cannon agrees, but he uncovers a few surprises in the process.
A case of vengeance. The girlfriend of a pro ballplayer is murdered.
The co-author of an industrialist's unauthorized biography is murdered.
Frank Cannon and Barnaby Jones investigate the rape and murder of a young woman who was about to blow the whistle on the company she was involved. But they are investigating for different clients and from totally different angles. [NOTE: Part two of this story continues on the TV series "Barnaby Jones.]
An ex-POW is in danger from a cowardly officer.
Dale and Laura Corey are a happily married couple who own an electronics store; he does a lot of electronic eavesdropping for clients, she was a cop on the force with Cannon a few years back, and hires him because Dale is being threatened after bugging some hotel rooms for the owner and catching three guests in compromising positions. The three are being blackmailed, and think Dale is behind it. Cannon interviews them and determines that one of the three is blackmailing the other two.
When a hunting accident turns out to be murder, Cannon steps in to clear his friend.