In a tiny hamlet of misty hills, twins arrive: a boy named Tatara and a girl called Sarasa. The seer Nagi proclaims that Tatara is destined to liberate Japan from the oppressive reign of the King and his four heirs. Yet when the merciless Red King kills Tatara, Sarasa adopts her brother's title and duties, setting out to free Japan and avenge the Red King through perilous trials across distant lands.