Season synopsis
Contains spoilers for this season and earlier seasons.
Columbo's investigations begin with a conductor who disguises his mistress's murder as suicide, only for a misplaced flower to expose a hole in his alibi. In other cases, a staged kidnapping becomes a real killing over trust-fund money, and a football executive uses a radio broadcast to fake a call from the stadium. The missing sound of a clock undermines that deception. Visiting London, Columbo encounters actors covering up their patron's death, then returns to a Hollywood star whose murdered assistant knew what happened to her missing husband.
In “A Stitch in Crime,” a surgeon uses dissolving sutures in a colleague's heart operation and kills a nurse who notices. Columbo pressures him into replacing the dangerous stitches, then discovers the removed evidence hidden in his own surgical clothing. Another investigation follows chess champion Emmett Clayton, who fears losing to Tomlin Dudek. Clayton pushes his rival into a garbage grinder, but Dudek survives the fall. He subsequently tampers with Dudek's medication to finish the killing. Columbo discovers that the machine stopped automatically, and demonstrates that Clayton could not hear the shutdown without his hearing aid.
The final case centers on identical twins Dexter and Norman Paris, whose wealthy uncle dies before marrying a younger woman. Each brother encourages suspicion of the other, while the death is disguised as a heart attack during exercise. Columbo reconstructs the real electrocution in a bathtub and the hurried movement of the body afterward. The brief power interruption and the physical work involved show that the plan required two people. Norman admits their joint involvement, ending the attempt to turn their identical appearances and supposed estrangement into protection from prosecution.