The story follows a young girl, Yume, who is clumsy and unpopular. While dozing in class, she has a vision of a young Miko, telling her that she must be the new Miko. She awakes with a mirror in her hands, and is confused by it. After school, the mirror reveals itself as a portal to a different world as a red-haired boy, named Rekka, appears chasing a unicorn, the peacekeeper of their world. The Azure Dragon of the East, or Seiryuu, shares that he is not happy a human of the Light world has become Miko, and tries to destroy Yume. None of the Guardians from the other world, except Rekka, believes in Yume. Rekka destroys the mirror so that the Other world-ers can not come through to harm Yume.

It is revealed that the world in which Rekka lives is suffering due to the Light world's exceptional development in such a short span of time. The Unicorn is the peacekeeper, and without the unicorn the world will become endangered. The goal of Yume and Rekka is to find the Unicorn and take it back to its home, as it is its own portal between worlds.

After a time of Rekka living in the Light world, he becomes the Kagura's cousin. Aoi, a boy at Yume's school, is soon revealed to be the King of the Eastern Skies of the Light world. Discovering this, the team decides they must find all the Guardians of the light world to help the Unicorn.