
Arsène Lupin has assumed the identity of Baron d'Enneris. Accompanied by Cissy Chevalier, who has concealed her profession as a journalist, he arrives in Locarno. There, he finds himself in the midst of a family drama: Adelina Da Ponte's wedding cannot take place because the famous papal medallion, a fabulous jewel and ancestral talisman, has been stolen. Everything seems to point to Adelina's brother Aurélio, who has disappeared. The medallion reappears around the neck of the beautiful Valérie Daubenton, wife of an international financier.
Arsène Lupin has assumed the identity of Baron d'Enneris. Accompanied by Cissy Chevalier, who has concealed her profession as a journalist, he arrives in Locarno. There, he finds himself in the midst of a family drama: Adelina Da Ponte's wedding cannot take place because the famous papal medallion, a fabulous jewel and ancestral talisman, has been stolen. Everything seems to point to Adelina's brother Aurélio, who has disappeared. The medallion reappears around the neck of the beautiful Valérie Daubenton, wife of an international financier.
Annoyed by the boasts of the new Minister of the Interior, Albert Rossignol, Arsène Lupin amuses himself by taking on the appearance of the new chief of security: Eugène Lenormand, whom the minister has just appointed with the mission of arresting Lupin. As soon as he takes office, Chief of Police Lupin-Lenormand is confronted with a series of murders that threaten the country's best interests and his own honor, since Arsène Lupin himself is accused of these crimes.