Végh Márta, the teacher is looking for her student Vadász Ica in the Buda villa, but she only finds the tenant, Mrs. Paár - dead. The investigation reveals that Mrs. Paár was murdered for an invaluable stamp, the "Fake Isabella".
Actress Jane Wilkinson wants a divorce, but her husband, Lord Edgware, refuses. She convinces Hercule Poirot to use his famed tact and logic to make her case. Lord Edgware turns up murdered, a well-placed knife wound at the base of his neck. It will take the precise Poirot to sort out the lies from the alibis - and find the criminal before another victim dies.
In Acapulco, Hercule Poirot attends a dinner party in which one of the guests clutches his throat and suddenly dies. The causes seem to be natural until another party with most of the same guests produces another corpse.
At the insistence of Ruth Van Rydock, an old schoolfriend who is convinced that there is something wrong, Miss Marple agrees to visit 'Stonygates', the country house of Ruth's sister.
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.