In Acapulco, Hercule Poirot attends a dinner party in which one of the guests clutches his throat and suddenly dies. The causes seem to be natural until another party with most of the same guests produces another corpse.
While attending a glamorous jazz cruise on New York’s East River, Nick and Nora Charles witness the fatal shooting of a wealthy patron. When suspicion falls on a young bandleader and his musicians, the couple steps in to clear their friends and uncover the real killer. Their investigation leads through a lively world of jazz clubs, radio personalities, high society, and backstage rivalries, where almost everyone has a secret and the next clue may be hidden in the music.