The Hollow Needle is a vel by Maurice Leblanc featuring the adventures of the gentleman thief, Arsene Lupin. Arsene Lupin is opposed this time by Isidore Beautrelet, a young but gifted amateur detective, who is still in high school but who is poised to give Arsene Lupin a big headache. In the Arsene Lupin universe, the Hollow Needle is the second secret of Marie Antoinette and Alessandro Cagliostro, the hidden fortune of the kings of France, as revealed to Arsene Lupin by Josephine Balsamo in the vel The Countess of Cagliostro (1924). The Mystery of the Hollow Needle hides a secret that the Kings of France have been handing down since the time of Julius Caesar... and w Arsene Lupin has mastered it. The legendary needle contains the most fabulous treasure ever imagined, a collection of queens' dowries, pearls, rubies, sapphires and diamonds... the fortune of the kings of France. When Isidore Beautrelet discovers the Chateau de l'Aiguille in the department of Creuse, he thinks that he has found the solution to the riddle .However, he did t realize that the chateau was built by Louis XIV, the king of France, to put people off the track of a needle in Normandy, near the town of Le Havre, where Arsene Lupin, kwn also under the name of Louis Valmeras, has hidden himself.