While on vacation at a resort hotel in the West Indies, Miss Marple correctly suspects that the apparently natural death of a retired British major is actually the work of a murderer planning yet another killing.

一位新婚燕尔的年轻女子突然被人杀害了。究竟谁是凶手？是她的丈夫，还是她昔日的情人、仇人抑或情敌？一对喜欢侦探的青年决心将此事查个水落石出。他们私访知情者，调查当事人，几经曲折，数历危难，克服了有人故意设置的层层障碍，躲过了杀人者的冷枪暗箭，终于使事实真相大白与天下……

A letter for Miss Marple from a recently deceased friend promises a large reward for investigating a crime - without telling her who was involved, or when it happened! When she accepts, she is given a reservation for a coach tour of historic homes and gardens. She has fifteen fellow-passengers - and one of them knows a murderer's secret and someone is preparing to kill.