This Miss Marple novel is not a sequel to "A Caribbean Mystery", but it does concern some characters from that novel - most notably Mr Jason Rafiel, a very wealthy man who Miss Marple reads in The Times has recently died. When she is contacted by a solicitor she has no idea what the reason could be, but it turns out that Mr Rafiel has left a puzzle for her to solve. Miss Marple is required to solve a crime - for which no details are given - and has a year in which to manage this. If she is successful, she is to be given £20,000.
Gradually, information comes Miss Marple's way. She is to go on a coach tour of historic homes and gardens. On the trip she meets people who slowly make clear the crime she is meant to solve. Finding the trip tiring, she is offered a rest at the home of three sisters, who also knew Mr Rafiel, and begins to piece together the mystery. This is a wonderful story - Miss Marple is quite elderly in the book, but her mind is as sharp as ever as she deceptively, and gently, teases information out. Interrogation hidden under clouds of fluffy knitting and benign questions. The ending is wonderful - you will cheer Miss Marple as she, of course, succeeds in her mission.