In a medieval Japan infused with fantasy, Takeo is a taciturn samurai searching for the truth about his origins and the reasons why he was raised in a monastery before being abandoned by his brother. Accompanied by his young disciple Shiro, he becomes caught in a vast conspiracy involving the powerful General Akuma, the Emperor, and the mysterious figure of the Thirteenth Prophet. Throughout his journey, Takeo faces warriors, assassins, occult forces, and ancient rivalries, while his personal quest gradually becomes intertwined with the fate of the entire Empire.