Miss Marple and Mr. Stringer are witnesses to the death by heart attack of elderly, rich Mr. Enderby. Yet they have their doubts about what happened. The police don't believe them, thus leading Miss Marple to yet again investigate by herself.

Miss Marple believes she's seen a murder in a passing-by train, yet when the police find no evidence she decides to investigate it on her own.

After falling in love with an American woman, Virginia Killain, who is engaged to another man, British Naval Commander Max Easton, hatches a plan that will get him enough money to support Virginia in the lifestyle she is accustomed to. Easton's plan is to disappear for a time making it seem that he has defected to the Soviets taking important Naval secrets from his job at the Admiralty and to return and sue the newspapers for slander. Not everything goes as planned for Commander Easton.

An Inshore Minesweeping Unit has been forgotten by the Navy after World War II on the peaceful island of Boonsley and they have adapted to their circumstances. The men still wear uniforms and the proper reports are filed, although the reports of hundreds of mines are exaggerated. The captain spends his time fishing, the Number One is busy romancing the only Wren on the island and The Chief Boatswain runs a wine smuggling business. Unfortunately the Navy start to get suspicious.