Ceres was a tennyo (Celestial maiden) who descended from the heavens to bathe in a stream. She hung her hagoromo (robe) on a nearby tree, which served as her means of returning to the heavens. However, the robe was stolen, and the thief forced her to become his wife, thereby creating a lineage with mixed human and tennyo blood. In modern times, Aya Mikage is a descendant of Ceres and possesses a significant amount of tennyo blood. On her 16th birthday, she and her twin brother, Aki, are thrown a party. At this "party," Aya's grandfather plans to kill her because she possesses tennyo powers unlike the rest of the family, and can actually become Ceres herself, potentially destroying the Mikage family. Aya, however, can switch back, so this transformation occurs quite frequently. With protector Yuuhi by her side, it is up to Aya to control Ceres and keep her from emerging, but her relationship with a former employee of her evil grandfather may serve as a distraction.