At the beginning of the story, we see Hanzo Hattori taking care of his unconscious child, Shinzo. Even though Shinzo's body is still functional, Hanzo is shattered by his inability to save his son's soul. While praying for Shinzo's reincarnation, Shinzo's soul briefly inhabits his body and informs Hanzo that Amakusa's soul is still present in the netherworld, urging Hanzo to defeat the antagonist. Nonetheless, Amakusa retaliates by sending Shinzo's soul back to the demon world and reducing his form to lifeless again. Driven by a blend of anger and anguish, Hanzo sets off to retrieve his son's soul.
