Prince Philippe of Bracowa must join his fiancée by train. The young and pretty Gisèle is on the same train, for her too to join her fiancé.
Poor Arlette is married off by her well meaning mother to a supposed count who turns out to be a fake and a crook.Arlette seeks out the real count, to whom in name technically she is married.
On his wedding night with Hilda Bergmann, the daughter of a swedish chemist, the young and rich american Willy Keanton is stabbed by an unidentified masked man. He kidnaps the young woman, who is found later on by the count Robert d'Arbel. The detective Jacques Miral, nicknamed « the pointed tower's ferret » is put in charge of the case. Soon, he discovers that an international bandit, Méphisto, seeks to seize the formula of a process against asphyxiating gas, invented by professor Bergmann. The struggle is tough between Miral and the uncatchable Méphisto. Monique Aubray, Keanton's secretary and engaged to the detective, the Nostradamus stallholders and the « mastiff of Bordeaux », and the famous novelist Fortuné Bidon are also involved in the case...
When a criminal named King Fu who has terrorized a city substitutes himself for a stage actor who looks like him, the staff and spectators at that night's show think the actor is giving an unusually good performance.
Paris, 30's declared professional rivalry between two stars of the musical, Yvonne and Gaby leads to dire consequences. Yvonne's body is found in the theater. Gaby's future is threatened against the judgment to which it is subjected, with a probable prison sentence.
