The series focuses on the heroine, Hitomi Kanzaki, and her adventures after she is transported to the world of Gaea, a mysterious planet where she can see Earth and its moon in the sky. On Gaea, Earth is known as the Mystic Moon or "Phantom Moon" (幻の月, Maboroshii no tsuki). Hitomi's latent psychic powers are enhanced on Gaea and she quickly becomes embroiled in the conflicts between the Zaibach Empire and the several peaceful countries that surround it. The conflicts are brought about by the Zaibach Empire's quest to revive the legendary power from the ancient city of Atlantis. As the series progresses, many of the characters' pasts and motivations, as well as the history of Atlantis and the true nature of the planet Gaea, are revealed.