Arsène Lupin is in Barcelona with the firm intention of stealing the famous Altarpiece of the Knights Templar. Thanks to a clever stratagem, he manages to enter the castle of Don Juan, Grand Master of the Order. But the famous burglar's meticulous plan proves much more difficult to execute than expected.

The gold belonging to savers, deposited in the vaults of the Suares bank, disappears inexplicably. To avoid a financial scandal, the government orders the police to keep quiet, even though they suspect Arsène Lupin.

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 seeks to steal the icon of Saint George, sparkling with diamonds. It is currently in the hands of General Krechov, a Russian émigré aristocrat who stole it himself and took it to Paris. This icon is also coveted by the Soviet government, which wants to sell it to buy wheat. Comrade Tatiana, a beautiful civil servant, is in charge of this mission. If she doesn't want to use her charms to succeed, she'll just have to hire a thief, Arsène Lupin for example! She travels to Paris, escorted by two henchmen. Lupin introduces himself to Comrade Tatiana, disguised as a proletarian.

The Baron and Baroness de Watrin, wealthy philanthropists, have decided to donate a famous diamond from their collection, the Pink Diamond, to the City of Brussels. Professor Einstein is to attend this highly scrutinized ceremony. When the day arrives, Arsène Lupin, who intends to steal the jewel, disguises himself as Einstein. Meanwhile, his faithful Grognard “occupies” the real Einstein by walking around the city with him. But then a group of extremists kidnap Lupin, mistaking him for the famous scientist.

Baroness von Kuhlen steals a gift from Arsène Lupin that he intended to give to a friend. That's all it takes for Lupin to concoct one of his devilish little schemes, the secret of which only he knows. Under the identity of Prince Renine, he visits Baron von Kuhlen, who owns a beautiful wine cellar, to buy some wine. He discovers that the baron has another passion: archaeology. He digs and searches everywhere, while his wife, out of boredom or provocation, picks pockets left and right.

To win the favor of the beautiful Duchess of Abrantes, descendant of General Junot, Arsène Lupin stole a cannon from Les Invalides. Under the identity of Lord Wellington, he offers her this strange gift, which is also coveted by the famous oil magnate, Mr. Arkadian. At the same time, Professor Da Silva, a Portuguese historian specializing in 16th-century navigators, whose niece is in love with Lupin, mysteriously disappears. This whole strange story masks the search for the wreck of the Santa Isabella, a frigate sunk in 1805 by one of Junot's cannons. Some say that the wreck contains the jewels of the Portuguese royal family who fled their country.

The wealthy Günther von Sand, tiger hunter and longtime friend of Raoul d'Averny, alias Arsène Lupin, was found murdered in his Munich home. His friend and sole heir, engineer Falkenberg, soon meets his death in the same mysterious circumstances.

The beautiful Countess Eléonore welcomes Prince Rénine, alias Arsène Lupin, into her home. An unknown woman breaks into the house and steals the painting given to the countess by the supposed prince. A few hours later, the painting is returned to its place. On the floor, at the foot of the painting, lies the body of a young man who bears a striking resemblance to the portrait on the canvas. The police burst into Arsène Lupin's home and charge him with murder. The gentleman thief manages a daring escape, but not before stealing the guards' pay...

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.

Stanislas Duchat, pianist, is shot dead as he prepares to perform an unpublished nocturne by the famous composer Frédéric Chopin. Arsène Lupin, who was present at the performance, decides to solve the mystery and travels to Poland, to the Kotovski castle.

During the assassination attempt on King Alexander of Yugoslavia in Marseille, the king's valuable watch disappears. Herlock Sholmes is tasked with finding it. He quickly concludes that the watch was not lost but stolen by a pickpocket from Zagreb. He immediately travels to that city. On the Orient Express, he meets Arsène Lupin, who is also looking for the watch. From then on, a fair duel ensues between the two rivals. A matter of state? A matter of money? A former mistress of the King, opponents of the Yugoslav regime, a beautiful adventuress: so many adversaries who will allow Lupin and Holmes to measure their talents.