While at this time the previous day he had never heard of the Martons, the train set specialist was beginning to haunt his thoughts, and so was the elegant young woman who, he admitted, had boldly stood up to him when he had done everything he could to unsettle her. When a salesman from a Paris department store confides his secret fears to Maigret, the Inspector soon becomes caught up in a treacherous feud between husband and wife that is not as clear cut as it seems.