Jane Marple is paying a visit to her old friend Ruth Van Rydock. The two, along with Ruth's sister Carrie Louis, wr all friends togethr at the same school in Italy when they were young women. Ruth, a wealthy, oft-married socialite, is worried that something is very wrong at Stony-gates, the Victorian mansion where her sister, Carrie Louis, lives with her husband Lewis Serro-cold. She can't explain any real reason for these worries, but she fears that Carrie Louis may be in danger of som kind. Ruth asks Miss Marple to visit hr and find out what is going on.