The Hollow Needle

An Ancient Fortress. A Royal Enigma. The Greatest Secret of the Kings of France. When a daring night-time robbery at the château of Count de Gesvres leaves behind a wounded accomplice and a series of impossible clues, the Paris police find themselves completely outmatched. But the true challenger to Arsène Lupin is not a veteran inspector; it is Isidore Beautrelet, a brilliant, teenage high-school student with an analytical mind that rivals the master thief himself.
As the young prodigy untangles Lupin's flawless misdirections, he uncovers a cryptic phrase that has been passed down through centuries: the secret of the Hollow Needle. This is not a simple hunt for stolen diamonds. Beautrelet's relentless pursuit forces Lupin to play a high-stakes, defensive game that threatens his entire empire and his carefully guarded anonymity. The trail leads directly to a massive, needle-shaped rock formation on the coast of Normandy-a legendary, hollow fortress that has hidden the immense treasures, crown jewels, and darkest secrets of the French monarchy since the days of Julius Caesar.
For Lupin, this place is not just a hideout; it is his sanctuary and his ultimate pride.