a future foretold
and the history repeats
The story of Ayashi no Ceres revolves around a teenage girl, Aya and Aki, her fraternal twin, the Mikage and Aogiri family, as well as those with celestial maiden blood in them. Before the twins turned 16, they hung out with their friends, and went to a fortune teller. Aya was told:
"You were born under the influence of a star of darkness... I see blood, anger, and suffering. The balance of this world will be destroyed. Upon the day of the arrival of the 16th star and moon, you shall meet your destiny. Whether in light or darkness, the great power deep within your soul will rise to the surface."
On their sixteenth birthday, they were 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 was proven to be a reincarnation of a tennyo (celestial maiden), and when her hidden memory is jogged, 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 soon found out that she was being hunted by her own family who plans to kill her. She was saved by Suzumi Aogiri, a C-Genomer (tennyo descendant) from Kansai, Yuuhi, a very energetic teenager and Suzumi's brother-in-law, and Touya, a mysterious man with whom Aya soon falls in love.
Events escalate as Aya struggled to control Ceres, and her brother gained the ability to manifest as Shiso Mikagi, the ancestor of the Mikage family who happen to have stolen Ceres' hagoromo (feathered robe) that will help her open the gate of heaven.
As Aya's allies increased, which include two C-Genomers like herself and the Aogiri family, and Touya, she managed 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.
Aya's quest to find Ceres' hagoromo wavered as she attempted to avoid her family, the organization carrying out the C-Project (Celestial Project), the advances of Shiso Mikagi, and the forces that threaten to tear her apart from Touya, whose lost memory may be the key to finding Ceres' hagoromo.
Touya soon learned that he was the organism that was created from the hagoromo or mana and his purpose was to return the mana back to Ceres. His love for Aya set him apart from everyone else.