Columbo unwittingly becomes part of a deranged woman's diabolical plot to destroy the two men she believes responsible for her husband's death in prison. After murdering one, she moves in on the other, Columbo, to kill the person closest to him, his wife.

After winning a $30 million lottery, photographer Freddy Brower, who wishes to keep the money a secret from the wife who is divorcing him, arranges with his uncle, wealthy jeweler Leon Lamarr, to pretend the lottery ticket is Lamarr's, until the divorce is final. Little does Brower know his uncle is having an affair with Brower's wife. Lamarr kills Brower in order to keep the lottery winnings for himself.

Given a deadline to pay his debts or else, chronic gambler Harold plants a bomb under the Rolls Royce of his uncle, sports magnate Big Fred. However, Big Fred is killed by a hit-and-run driver while jogging that very morning, and the Rolls Royce explodes when Fred's gardener tries to move it out of the way of the TV camera crews. Just when Columbo thinks he has the goods on Harold, it is Harold who turns up dead.

Nick Franco is a violent, two-timing gigolo and his current paramour, Laura Stanton, has had enough. With the help of a young woman named Lisa, she murders her lover and sets herself up with an airtight alibi. When Columbo starts sniffing on her trail, Laura quickly works to seduce the married detective, hoping that her sex appeal will throw the usually stubborn Lieutenant off the scent.

A photograph is the only clue for Columbo when two dead men and a seven year old mystery with $4 million dollars involved as well as an obnoxious insurance investigator come into play.

Graham McVeigh, a thoroughbred ranch owner, kills his brother, and frames a local mob bookie. Then, under the guise of making good on his brother's debt, he kills the bookie as well, claiming self-defense. Mob boss Vincenzo Fortelli starts to exert pressure on McVeigh. To solve the crime Columbo must work with the gangster.

Cathleen Calvert and her lover, crime scene investigator Patrick Kinsley, plot to get rid of Calvert's husband, Clifford, a powerful businessman, by killing an investment broker with whom he is currently feuding, and pinning the murder on Clifford. As long as he is alive and in prison, Cathleen has access to all his money. Columbo must uncover a criminal who is part of the team handling the investigation.