Synopsis
Japan is secretly ruled by a ruthless ninja organization known as the Shinogara. Their deadliest assassin is Hayate Kanuma, whose father is the leader of the Shinogara. But Hayate believes the secret society's grip on Japan is unjust. Risking everything, he kills his father and becomes a fugitive. With few safe havens from his vengeful former allies, he chooses one unlikely refuge: his sister. After suffering a possibly fatal wound, Hayate manages to transfer his soul into his sister's body, briefly sharing it with her. His sister, Shiori, can summon Hayate and tap into his ninja skills when the Shinogara are near—but each time she does, she loses more of her own identity. This arrangement cannot last forever, so how will Hayate ultimately defeat the Shinogara?