The island is celebrating its Day of the Dead, which literally lives up to its name when Daisy Anderson, organizer of a charity auction at the local yacht club, is murdered after sending a frantic message to her husband Finn. She had had a brief affair with club member Adam Warner, about which Finn knew, and was filing for divorce, as well as discovering a fraud perpetrated by club treasurer Charlotte Hamilton. However all three have alibis. Jack is mystified by the appearance of a butterfly which should be in hibernation on Daisy's body but it gives him a clue to solving her murder.