An example of the classic detective novel of the Golden Age. The case of the poisoning of Sir Eustace—the rake and ladies’ man, the notorious seducer of other men’s wives—at first looks fairly simple: all you need to do is find among the many deceived husbands the one who is the most jealous, capable even of murder. But then something incredible happens: every one of the amateur detectives is absolutely sure that their own suspect is the culprit!..