Moeyo Ken Plot Summary: Set in an alternate version of the Meiji Era, a boy named Ryūnosuke Sakamoto returns to Kyoto from Shanghai with his monster (yōkai) Nekomaru. The law states that in order to live freely with humans, a yōkai must be licensed. The Kidō Shinsengumi Co. Ltd. is responsible for the capture of unlicensed yōkai but must fight with the Tsubamegumi, who resent the new law. It turns out that Ryūnosuke is the son of the owner of the Shinsengumi.