In a small village, twins are born: a boy, Tatara, and a girl, Sarasa. The prophet Nagi declares that Tatara is the chosen one who will free Japan from the tyrannical rule of the King and his four sons. But when the ruthless Red King slays Tatara, Sarasa must take on her brother's name and responsibilities and embark on a quest to free Japan and deliver vengeance to the Red King.

(Source: Anime News Network)