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. ......