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.
Hallie Parker and Annie James are identical twins who were separated at a young age due to their parents' divorce. Unbeknownst to their parents, the girls are sent to the same summer camp, where they meet, discover the truth about their relationship, and come up with a plan to switch places in an effort to reunite their mother and father.
When two trouble-making brothers scam their way into an idyllic summer camp, they find themselves leading a rag tag cabin of boys into breaking every rule in the book.
Detective Guy Johnson's client, Willie Heywood, is framed for murder. While Guy hides him so he can catch the real killer, both of them are nabbed by the police, tried, convicted and sentenced to jail: Guy for a year with Willie to be executed. On the way to jail, Guy comes across a clue and escapes from the police.