Mannix looks into why someone might want to kill one half of a successful singing pair, after a nearly fatal accident.
Kidnappers have the daughter of Mannix's good friend, who is also Mannix's god daughter. They demand her father lose a great deal of money in a card game as her ransom.
One might think that after waking from a year long coma, the worst would be in the past. But that is not true for Mannix's client, injured in a hit and run accident and now the target of killers.
Syndicate thugs have kidnapped an informer - or so they believe. Their victim is actually Peggy Fair, Mannix's secretary, which puts Mannix on their trail.
Mannix searches for a counterfeiter who has disappeared. He's up against Federal agents and criminals who want the man's flawless plates.
Mannix's search for the source of a death threat takes him to a small town. Shortly after he arrives, he's framed for murder and imprisoned. His freedom and future will depend on figuring who hates him this time, and why.
Mannix loses a friend - a small time mob courier killed flying money to Mexico. The mobsters, certain Mannix stole their money, come after the detective determined to recover what's theirs.
A courier is abducted while en route to the Japanese consulate. Joe helps Tami Okada, a Japanese investigator trying to find the man.
Mannix finds himself drawn to a woman in a photograph - a murder victim. He sets out to see her killer jailed.
Mannix travels to New Mexico to prove that an Indian's death was murder. But the townsfolk don't seem to like Indians, which means they don't much like Mannix, either.
A man survives a plane crash - or does he? His wife has her doubts, so Mannix looks into it for her.
Mannix looks into a businessman's murder, and discovers that his wife may have been the real target.
Mannix's military comrade broke under torture. Haunted by that, he sets out to prove such treatment would also break Mannix, capturing and torturing the detective to prove his point.
Someone murders a friend of Mannix's who was also a detective. Mannix discovers the man worked for a mafioso and sets out to learn why he died, despite pressure to stop digging.
Two buddies from Vietnam meet and one of them ends up dead. The murder might be connected to a third man, a deserter still evading the authorities.
An anthropology professor comes to believe one of his students had an affair with his wife, and denies the man a degree. Then someone murders the professor, and the police come knocking, leaving Mannix the young man's hope for freedom.
Someone demands a quarter of a million dollar ransom - for a boy missing six years!
Thieves plan to start a holiday weekend by looting every office in a high rise. That leaves Mannix and a friend trapped in the man's vault, with limited air and no one likely to discover them for several days.
Joe agrees to help a mechanic whom police have accused of beating an inventor to death.
Mannix's client hires him to find the man who saved his son's life. The search takes him to an island near South America, and then the next link in the chain turns up dead.
Still searching for the man who saved his client's son's life, Mannix stumbles into the ugly side of politics: an assassination plot.
A politically ambitions publisher hires Mannix to find evidence that his wife is cheating. When Mannix has no trouble finding this evidence, he begins to question the reasons he was hired...
A man hires Mannix to locate a dead body. But the man is the murderer, a contract killer who wants to clean up after himself - which might include dealing with a nosy private detective...
A drug dealer and his gang take several hostages to force Mannix to locate and retrieve another member of the gang, who betrayed them. Mannix fears someone's going to die no matter what he does.