Like the R Season, Sailor Stars is divided into two arcs: The first arc (also filler) solves some conflicts from the SuperS season, and also sees the return of the Outer Senshi, Haruka, Michiru, Setsuna, and Hotaru (now reborn as a child). The second arc is the actual plot from the manga. Usagi bids farewell to Mamoru, who is going to America to study abroad. In his place comes the Three Lights, an idol trio consisting of three boys, Seiya, Taiki, and Yaten. The new enemy is Galaxia, a woman who desires to rule the entire galaxy by collecting the Star Seeds of humans. Three new Senshi appear, the Sailor Starlights, who also intend to stop Galaxia without Sailor Moon's help.

In ancient times, a group of young men devoted their lives to protecting Athena, the Goddess of Wisdom and War. These men were capable of fighting without weapons—a swing of their fist alone was powerful enough to rip the very sky apart and shatter the earth beneath them. These brave heroes became known as Saints, as they could summon up the power of the Cosmos from within themselves. Now, in present day, a new generation of Saints is about to come forth. The young and spirited Seiya is fighting a tough battle for the Sacred Armor of Pegasus, and he isn't about to let anyone get in the way of him and his prize. Six years of hard work and training pay off with his victory and new title as one of Athena's Saints. But Seiya's endeavor doesn't end there. In fact, plenty of perils and dangerous enemies face him and the rest of the Saints throughout the series. What new quests await the heroes of the epic Saint Seiya saga?

The god of war and guardian of his namesake planet, Mars, was once sealed away by Seiya, but time has passed and his revival is at hand. Meanwhile, Saori Kido (Athena) is raising the boy Kouga, whose life Seiya saved, and he's been training every day to become a Saint in order to prepare for the coming crisis... Unaware of his destiny, when Kouga awakens to the power of his Cosmo hidden inside him, the curtain will rise upon the legend of a new Saint. (Source: ANN)

The whole Sanctuary was misled into danger due to the civil war instigated by the Gemini Gold Saint, Saga. Our story begins right after the end of those events... This is a story of the girls protecting Athena. These are the records of love and fierce fights they meet while opposing destiny on their way to maturity... (Source: MangaSeven)