Set in an alternate Meiji era, a boy named Sakamoto Ryunosuke returns to Kyoto from Shanghai with his yokai, Nekomaru. The law states that in order to live freely with humans, a yokai must be licensed. The Kidou Shinsengumi Co. Ltd. is responsible for the capture of unlicensed yokais but must fight with the Tsubamegumi, who resents the new law.