Summary: The story revolves around a teenager girl named Aya and her twin brother Aki, members of a wealthy and powerful Mikage family. On their sixteenth birthday, they are called to gather in their family home to be given a special present. The present was actually some sort of test -- which Aya failed. She is found to be a reincarnation of a tennyō(celestial maiden), and when shaken, she will transform into Ceres, the tennyo. According to the legend, if left to live, the reincarnation of Ceres will bring ruin upon the Mikage family. Aya quickly found she is hunted by her own family who plans to kill her. She is saved by Suzumi Aogiri, another tennyo descendant, and quickly falls in love with a mysterious man, Tōya. Along with Tōya, she meets Yūhi, a very energetic teenager (who is Suzumi's brother-in-law). Events escalate as Aya struggles to control Ceres and her brother gains the ability to manifest as the "Progenitor", the ancestor of the Mikage family who happen to have stolen Ceres' hagoromo (celestial robe) that will help her open the gate of heaven. As Aya's allies increase, which include two tennyo like herself and the Aogiri family, and Tōya, she manages to reach a compromise with Ceres such that Ceres will not manifest herself without Aya's approval so long as Aya manages to recover Ceres' lost hagoromo.