Lately Hercule Poirot has been receiving tiresome requests for his detective skill--lost dogs, missing jewelry, and the like. When an urgent letter begs him to come to the South of France for a mystery that cannot involve the police, Poirot hops on a train, his interest peaked. He arrives to find that the author of the letter has been murdered in the night and his distraught wife professing ignorance of motive or suspect.