Hayden Danziger, a young, affluent man treats his older and wealthier wife, Sylvia, to a vacation on a cruise ship. Also on the ship is Hayden's mistress Rosanna, who is performing on stage throughout the cruise. When Rosanna attempts to blackmail Hayden by telling his wife the truth, he decides to kill her and has plans the perfect crime. But when the crime is discovered, a vacationing Columbo is asked by the ship's captain for help in solving the crime. Stars Peter Falk, and Robert Vaughn.