Inspector Bérurier, having inherited a mansion three years earlier, comes to collect rent from the tenant when the latter is murdered under mysterious circumstances. Béru calls Commissaire San Antonio to the rescue, and the two men discover that Laurenzi's hotel is home to a "brothel" whose director, Madame Albertine, soon reveals to the two policemen that Laurenzi was having an ongoing relationship with Helga, one of the boarders, and Mr. Max, a regular guest of the house.