Arsène Lupin decides to run a detective agency in addition to being a gentleman thief. As a detective he happens to cooperate with police in order to unveil the criminal activities of a villain. When he succeeds the villain returns the favour. The unmasked Arsène Lupin manages to escape with the villain's gangster moll as his new companion.

At the end of the Great War, Arsène Lupin resumed his adventurous life. Theft of three paintings committed by an adversary leads him to the treasure of the Golden Fleece.

André Laroche, an industrialist, has just passed away. Face to his grave, as he is being buried, Anne de Vierne, the wife of a magistrate, confesses to her son François that Laroche was in fact Lupin and that he is his natural child. But he is not the gentleman thief's only offspring! Lupin had indeed another son by a housemaid, Gérard Dagmar, a dancer, magician and - occasionally - burglar. Which complicates the task of François who, to respect the last wishes of the testator, has gone in search of the treasure of Poldavia. For he keeps finding Gérard on his way and his efforts are constantly thwarted by his half-brother. Will Gérard prevent François from becoming the worthy successor to their father or will the two young men decide to join forces? That is the question.

The Adventures of Arsène Lupin follows the tale of a charismatic thief who leads a double life as a wealthy gentleman in high society. Lupin utilizes his wit and cunning to carry out daring heists, kidnappings, and uncover hidden treasures. Based on the popular novel series, Lupin navigates the world of crime and mystery as he outwits his adversaries and indulges in a life of thrill and adventure.