Yuzo Kayama is an American-Japanese operative working for the US to uncover an arms deal between an American seller and Chinese communists, and to take out both parties. After almost getting assassinated himself, he takes a wounded civilian with him despite living in a world where no one can be trusted.

A civic music group, created by Tsukasa Nitta, a high school teacher in Koriyama City, and Akiko Watanabe, the daughter of a record shop and teacher of a music class, invites Takuro Yoshida to Koriyama City to hold a concert. He then starts being harassed by the Hashimoto group, a local gangster group which manages the city's entertainment.

A mysterious thief called "Yami no Kiba" (Fang of Darkness), who sneaks into the residences of the shogunate one after another and steals the shogun's treasures, has been shaking the public authorities. The identity of the thief is Ichibei, a medicine seller whose father was once killed by the shogunate, and his daughter Oasa. Ichibei had been seeking revenge against the official to avenge the death of his father, Sasajima Hyobu, who was a member of the Kurokuchi clan, the official ninja. He was also plotting to seize the gold orca of the Nagoya Castle keep, aiming at the Owari clan that had slain his father. ......