Set during the Kyoho Period of the Edo Era (1716-1735), the city of Edo (now Tokyo) is under the terror of Okami Kamen (Wolf Mask). Town Magistrate, Echisen Ooka, send his top man in the Kage Yoriki (Shadow Police), Hyoma Tsurugi (Kyotaka Mitsugi), to investigate. He unveils the evil pulling the strings of a Yokai army, Kaen Daimaoh (Infernal Devil), but is mortally wounded by the creature. Suddenly, another apparition appears, Shiro Jishi Kamen (White Lion Mask), who spares his life — and now Tsurugi must fight as the human form of this agent of righteousness to preserve justice!