An Irish poet, who fronts a peace organization while secretly running guns, kills an arms dealer who tries to swindle him.

A famous psychiatrist uses an appointment with his doctor as his alibi while he calls his house, where his dead wife's lover is. The call serves as the first step in a conditioning reflex on the psychiatrist's dogs. The other part is the word Rosebud as uttered by the victim. When Columbo arrives on the scene, the psychiatrist is very understanding when police say they may have to put his dogs to death. But Columbo notices how friendly the dogs seem, and then there's the telephone that's hanging from it's hook.

Mark McAndrews a top network programmer is promoted to a New York position. His assistant, who is very ambitious and his lover, expects to get his old job. But of course he feels she is out of her league and needs more experience. Kay, feeling betrayed, decides to seek revenge.

A famous food critic is threatened by a restaurant owner, and so the critic leaves. Soon after, the cook dies. Columbo's involvement is welcomed by all the other chefs in the area, but Columbo wonders why the dead restaurant owner slammed the drawers before he died. And how could the poison that killed him enter an unopened bottle without the killer even being in the room? Could it have been suicide? But then there's the cheques to a mysterious society, and the victim's calender. Can Columbo's cooking skills really match the food critic's taste?

A writer of murder mysteries wreaks revenge on her nephew-in-law by blaming him for her niece's murder.