Fumio Onishi was originally supposed to find out who murdered his friend Yuki in Berlin for the Japanese mafia. However, he was drawn into an excessive quest for revenge against the Vietnamese clans behind Yuki's death and subsequently fled to Tokyo with his German girlfriend Nikola. Here, the Yakuza boss Oyabun Takeda demands accountability, as Fumio's unilateral actions have brought serious problems to the Yakuza. In this situation, Fumio seeks help from his old teacher, Master Harada, but Harada himself is in grave danger. While Christoph Peters has illuminated the bright, fascinating, and sometimes quirky side of Japanese culture in his novels "Mitsukos Restaurant" and "Mr. Yamashiro Prefers Potatoes," he also delves into the depths in his second novel about Fumio Onishi, "The Arm of the Kraken.".