Inspector Ferrot meets Sylvia, an intriguing woman, on one of his missions and an affair begins between them. He becomes jealous, thinking that the young woman has another lover but unaware that it is in fact Ganay, his superior. One evening he argues with her in front of her home before several witnesses and Sylvia is murdered by Ganay later that night. Ferrot, who is put in charge of the inquiry, finds himself trapped as all the leads point to him....