 When the duke exhibits his collection, a policeman on guard recognizes the portrait as being that of one of Bluebeard's victims.Inspector Lefevre (Nils Asther) of the Sûreté calls in one of his best undercover agents, Francine (Teala Loring), who happens to be Lucille's sister.She and her "father" go to Lamarte to have her portrait done.