Ceres was a tennyo (heavenly maiden) who descended from the skies to take a bath in a brook. She hanged her hagoromo (robe), which was her ticket to returning to the skies, on a nearby tree. However, the robe was taken, and the thief compelled her to marry him, giving birth to a family with a mixture of human and tennyo blood. Aya Mikage, now living in modern times, is a descendant of Ceres and carries a significant amount of tennyo blood. Her twin brother, Aki, throws her a party for her 16th birthday. Aya's grandfather intends to kill her at the "party," because she, unlike the rest of the family, possesses tennyo abilities and can transform into Ceres herself.