In utter disbelief, Jane Marple read the letter addressed to her from the recently deceased Mr. Rafiel — an acquaintance she had met briefly on her travels. He had left instructions for her to investigate a crime after his death. The only problem was, he had failed to tell her who was involved or where and when the crime had been committed. It was most intriguing.

Soon she is faced with a new crime — the ultimate crime — murder. It seems someone is adamant that past evils remain buried...

Belgian detective Hercule Poirot is summoned to France after receiving a distressing letter with an urgent cry for help. Upon his arrival in Merlinville-sur-Mer, the investigator finds the man who penned the letter, the South American millionaire Monsieur Renauld, stabbed to death and his body flung into a freshly dug open grave on the golf course adjoining the property.

Meanwhile, the millionaire's wife is found bound and gagged in her room. Apparently, it seems that Renauld and his wife were victims of a failed break-in, resulting in Renauld's kidnapping and death.

There's no lack of suspects: his wife, whose dagger served as the weapon; his embittered son, who would have killed for independence; and his mistress, who refused to be ignored - and each felt deserving of the dead man's fortune.

The police think they've found the culprit. But Poirot has his doubts. Why is the dead man wearing an overcoat that is too big for him? And who was the impassioned love-letter in the pocket for? Before Poirot can answer these questions, the case is turned upside down by the discovery of a second, identically murdered corpse...