With the help of his friend Nathalie, Arsène Lupin steals the “Queen's Necklace”, owned by the Dreux-Soubise family. The theft becomes an affair of state, a matter of concern for the Minister and the Prefect of Police. Herlock Sholmes, the English detective, provokes Arsène Lupin. They agree to give each other four days to find the necklace hidden by Lupin in his Normandy château.

In Cannes, Arsène Lupin, posing as a policeman, finds himself entrusted by Guerchard with overseeing an exhibition of solid gold statues. Kesselbach, one of the exhibitors, boasts of possessing an absolutely inviolable safe. But Lupin knows that the man murdered Professor Ramirez in order to retain sole possession of the Inca treasure. In his normal guise, Lupin pays Kesselbach a visit.

Shortly after Arsène Lupin visits a Normandy château, a corpse is discovered. Astonishment... because, as Isidore Beautrellet, a young reporter sent to the scene of the crime, points out, Arsène Lupin steals, but never kills. A clever reporter, so clever in fact that he discovers the murderer: the Comte de Gesvres. Lupin, seduced by Beautrellet's perspicacity, invites him to witness his next exploit: to seize the medieval statues of the Château de Gesvres and replace them with casts.

Avenging Joan of Arc and Trafalgar, Arsène Lupin robs the Tower of London. Fabulous booty: the Crown's treasure and, above all, a priceless parchment, a thousand-year-old relic shrouded in mystery, the secret of William the Conqueror. Herlock Sholmes is assisted in his investigation by the Intelligence Service, the French 2nd Bureau, Commissaire Guerchard and journalist Isidore Beautrellet. A scholar tells them that a copy of the famous parchment, of which he has transcribed indecipherable passages, was stolen from a monastery in Normandy five years ago...

After witnessing his fake death and funeral, Arsène Lupin prepares to go on vacation. A vacation they forgo to accompany a beautiful stranger, Catherine, to a Norman manor house where a mysterious “man in a black hat” is making menacing appearances.

The millionaire businessman Prévailles has just married the young dancer Jenny Saphir, whose career he has pushed. A few years earlier, Jenny had fallen madly in love with Lupin. Lupin, aware of Prévailles' activities, disguises himself to warn Jenny of the danger she's in, and to protect her. For she possesses the sapphire of Genghis Khan, a priceless jewel with a legendary curse, a gift from General Ignatieff, one of the dancer's previous admirers.

Arsène Lupin swaps his burglar's tools for those of a jeweler to steal ten million francs worth of diamonds. Dressed for the opera gala on behalf of diamond merchant Van Houven, model Régine, star of a major fashion house, is kidnapped.

Arsène Lupin assumes the identity of Prince Paul Sernine, invited to take part in Baron d'Aigleroche's hunts. Baron d'Aigleroche lives with his niece Hortense and cousin Gaëtan. Lupin covets a richly illuminated Book of Hours that the Baron keeps in a safe.

Irène Imbert's life in 1926 is no more edifying than her wartime escapades with American pilots showered in dollars. Her cynicism gives Arsène a brilliant idea. Posing as a notary, he comes to tell the young woman that one of his former “war godchildren”, Henry Bradford, has made her his universal legatee. As a result, Irène finds herself at the head of a considerable inheritance. In the meantime, crooks and shady financiers are jostling for position at her door.