The film takes place in feudal Japan and follows Kibagami Jubei, a mercenary swordsman who battles the Eight Devils of Kimon, a team of ninjas with supernatural powers who are intent on overthrowing the Tokugawa shogunate. During his quest, he is aided by Dakuan, an elderly but crafty government spy, and Kagero, a Kōga kunoichi whose body is infused with poisonous toxins.