Shoko is a student at Ryuusei Private Academy Middle School. Her dear sister, Kyoko, had went to study abroad five years ago and hasn't heard from her since. One day, an unknown entity suddenly attacks Shoko. The ones who attacked her had been the Dryads, underlings of the evil goddess, Eris, who was once sealed by Goddess Athena. When Shoko and Saori Kido awaiting the Galaxian Wars meet, the gears of destiny begin to turn.

Kyoko's Cosmo disappeared in the battle at Eris' temple. Saori's heart wavers as she questions her existence from not being able to save Kyoko in defeating the evil god. However, with Saori inheriting Mitsumasa Kido's will, the Galaxian Wars start without mercy. On the other hand, Shoko who was in the hospital had been depressed from Saori telling her goodbye, and she drops the pendant of Pegasus given to her by her sister. The boy who caught it for her was Pegasus Seiya who was entering the Galaxian Wars.