Louis Kelveller, nicknamed the German, a born detective, exiled from the Ministry of Internal Affairs for knowing too much, finds a suspicious little bone under a tree. From this discovery—a phalanx of a human finger that ended up in Paris inside the stomach of a vicious pit bull—the investigation begins and leads Kelveller to a remote corner of Brittany. An unusual clue will help Louis, driven by an unstoppable thirst for justice, find the cruel murderer with the help of two young historians—Marc Vanduzler and his friend Matias—who are sure he is invincible.