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.