Atsuko's sister Hina is dying. With no money and no hope left, he has only one last resort: the Spirit Vault—a mythical battle royale between life and death. Here, the participants fight using supernatural powers. But for him, more is at stake than fame or power—it's Hina's life. And for that, he would do anything. Walk over dead bodies. Betray. Kill. Even his best friend. As alliances form and shatter, the lines between humanity and madness blur. The law of the Spirit Vault is relentless: there can be only one winner. And Atsuko vows to be that winner—no matter the price he must pay. Will he succeed in turning little Hina's fate around and passing the toughest tests of his life?