Miss Marple remains restless in her cozy home in the village of St. Mary Mead. This time, she's determined to intervene in the fate of her old friend, Carrie-Louise. Their mutual acquaintance, Ruth van Rydock, is convinced that the unfortunate woman is in danger of dying from poisoning. There's no evidence, but Mrs. van Rydock is convinced of the seriousness of the threat. Arriving at the home of Carrie-Louise and her husband, Miss Marple discovers their numerous, complex family members. Before the detective had time to settle in, she witnessed a crime: one of the family members was shot dead under the most mysterious circumstances. Thus, Miss Marple will have to investigate two cases at once: a murder and a possible poisoning; and, at first glance, there seems to be no connection between them.