The Crystal Stopper

Following yet another daring robbery, the Minister and the Prefect of Police call on a policeman unknown to Lupin, stationed in Africa: Victor offers to play the part of a clever worldly burglar, Mister Lorchester. In this way, he becomes part of Lupin's gang, whose only task is to arrest him. But to make him look the part, Victor needs a well-funded bank account, which the enthusiastic Préfet immediately opens for him. During his evenings of idleness, Victor Lorchester meets a young woman he believes to be Lupin's friend.

During a reception at the home of the brilliant young Maxime Bermond, the guests learn that banker Dautrec has just purchased the priceless royal diamond. Back at home, Dautrec checks the locking systems on the doors and windows. A nun is waiting to read to him. Shortly afterwards, an alarm goes off in the house. The servant finds his master murdered.

Lupin, posing as Bernard d'Andrezy, visits Gournay-Martin, the wealthy champagne owner. A reception is held, during which the guests tour the cellars. During the tour, Andrezy makes strange chalk marks on the walls. In the evening, a telegram upsets those present: “Arsène Lupin is among you”. The Prefect of Police takes an immediate interest in the case, and one of the guests accuses Andrezy of being Lupin, having noticed his strange behavior in the cellars. A manhunt begins, and Lupin ends up trapped in a cul-de-sac. His old enemy, Commissaire Guerchard, has the pleasure of handcuffing the notorious burglar for the first time.

Inspector Bechoux suspects Barnett, a private detective in whom he believes he recognizes Arsène Lupin, of stealing “King Dagobert's treasure” and hiding it. Barnett goes to the church in a small village where Inspector Bechoux has begun his investigation. The theft was committed in the middle of the night by a one-armed man. So Bechoux arrests a one-armed man in the village, interrogates him and hands him over to Baron de Gravières, the local Châtelain, for safekeeping. But Barnett isn't happy with this hasty arrest.

Arsène Lupin follows a young English woman on a train who has stolen his wallet. They are attacked by two men who flee when they realize they have the wrong victims. Lady Bakefield, wounded, faints, whispering to Lupin “Gabriel... Villa Valdblick”. Two corpses are discovered at the train stop. A young girl with big green eyes is arrested.

In the port of Amsterdam, a trunk containing a drugged man and top-secret scientific documents from the Ministry of National Defense is discovered. In order to find the source of the leaks and dismantle the spy organization, the authorities call in an unusual personality: Arsène Lupin. The gentleman burglar begins an investigation across the city. He befriends a young woman, Hélène, who belongs to the organization, and manages to get in touch with its leader.

Arsène Lupin has settled in Rome as a painter named Arthur Lodin. Always on the lookout for new adventures, he occupies the apartment next door to the wealthy Marquis Belmonte. One day, he is mistakenly visited by a beautiful blonde woman who has come to see the marquis. A few moments later, Commissaire Gorgone bursts into Lupin's apartment. He searches for the young woman and declares her to be “Clara la blonde”, the accomplice of the notorious Italian thief Peppino. Lupin, who has just enough time to hide his visitor, leads the superintendent on a false trail.

In Ungoldingen, at the small railway station, two unusual characters, the famous London detective Fox and his assistant Robertson, entrust their luggage to a porter who immediately disappears after leaving them a calling card bearing the message: “Arsène Lupin welcomes you”. Despite this incident, Fox and Robertson make their way to Augstadt Castle, where the owner, Baron von Augstadt, awaits them.

A gang is scouring St. Moritz, replacing real jewels with perfect copies. At the request of the insurance companies, Lupin arrives on the scene disguised as Raoul d'Andrézy, with a stolen piece of jewelry that will enable him to infiltrate the gang. Seeing that all guests at the palace where he is staying are being searched, Lupin slips the jewel into the pocket of Marie Bonatti, a young journalist, who leaves the hotel unchecked.

Arsène Lupin, disguised as Raoul d'Andrézy, travels to Vienna to attend a conference on treasures. At the home of wealthy Baron Ordosczy, the conference begins. Corcoran explains that the mysterious inscriptions engraved on 7 rings conceal the secret of Cagliostro's treasure. The light goes out. When it returns, the rings have disappeared.

Tornbüll Castle seems to be the center of a feverish tourist activity, which greatly displeases its owner, the young Count Stephan. Among the visitors is a gangster-like man who has the Count worried about his magnificent collection of paintings. Another character, as picturesque as he is disturbing: Lupin, disguised as the crippled English novelist Lord Lewcastle. Lord Lewcastle-Lupin urges Count Stephan to make copies of his paintings and lock the originals in his safe. He even recommends a young French artist for the job.

Maurice Leblanc, the author of Arsène Lupin, is in Brussels for a report and meets the handsome Jean d'Aspry, Arsène Lupin's temporary identity. One evening, Leblanc receives a mysterious message: “Whatever happens, don't move, or you're a dead man”. Terrified, Leblanc spends a very bad night in a house full of extravagant commotion. The next day, he is shocked to read about his night in the newspaper.