'A Caribbean Mystery' (ITV, tx. 25/12/1989), screenplay by T.R. Bowen, directed by Christopher Petit

Recovering from an illness, Miss Marple goes to stay at a hotel in Barbados. There she meets Major Palgrave, who once worked for the police in the British colonies. During one of his many interminable stories he tells Miss Marple of a man who is now on the island and who he thinks murdered his two previous wives, disguising the crimes as suicide. He is just about to show her a photo of the man when a group of other guests arrives. The group includes the British couple Edward and Evelyn Hillingdon, the Americans Greg and Lucky Dyson and Cockney millionaire Jason Rafiel, all under the watchful eyes of the hotel proprietors Tim and Molly Kendall. Palgrave quickly hides the photo in his wallet and changes the subject.

That evening the Major appears to be drunk at dinner. He is later found dead, apparently as a result of his high blood pressure. Molly seems to be hit the hardest by the event, worried about the effect this might have on the business. The hotel maid, Victoria, takes Miss Marple to visit her Aunt. The two elderly women soon make friends and Miss Marple learns a little of Molly's unhappy family life before marrying Tim. Victoria tells Molly that the blood pressure pills which she found in Palgrave's room had never been there before.

Miss Marple becomes suspicious of Palgrave's death when she learns that the photo of the man he meant to show her is missing from his wallet. She convinces the doctor to have the body exhumed. Victoria gives the blood pressure pills back to Dyson, from whom they were taken. Molly tells Evelyn that she feels as if she is being watched all the time. After dinner Molly arrives covered in blood. The stabbed body of Victoria is found nearby.

Rafiel, having been rude to everyone else at the hotel as well as his staff, apologises to Miss Marple for his behaviour and asks to talk to her. She admits to him that she is convinced that Palgrave and Victoria's deaths are connected. She also tells him that she fears that another murder may occur, reasoning that the person in the photograph must have killed Palgrave because they are planning to commit another murder.

The autopsy reveals that the Major was poisoned and that the effect of the drug would have made him appear to be drunk before causing a cardiac arrest. Edward Hillingdon has been having an affair with Lucky Dyson. Evelyn overhears her admit to having mercy killed Dyson's first wife when she worked for him as her nurse.

Molly overdoses on sleeping tablets, but recovers. The doctor fears that she is in the early stages of persecution mania. Miss Marple finds a book on psychosis hidden under Molly's mattress. She later sees Rafiel's employee Mr Jackson leave Molly's bathroom after checking her medicine cabinet. Miss Marple asks Rafiel if he is planning to leave anything to Jackson and his secretary Esther. He says he isn't, but later Jackson tells her that in fact Esther will receive £55,000 upon his death and that he has told her this. At dinner, Edward tells Evelyn that the affair with Lucky is over and that he wants to try for a reconciliation.

That evening Molly goes missing. During the search, Lucky's body is recovered from the beach. She is wearing a white bathing costume similar to the one Molly is wearing. Miss Marple and Jackson lie in wait at Molly's house. When she returns, her husband Tim tries to poison her but Jackson stops him. Miss Marple explains that Tim wanted to kill Molly so that he could marry Esther for her inheritance from Rafiel. He killed Palgrave to protect his plan and killed Lucky by mistake, thinking that she was Molly. He has been giving Molly mind altering drugs to make her seem unbalanced and suicidal. Miss Marple gladly returns to her home at St Mary Mead.