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.

Recap of leading up to the seventh season.

In the world of Prester, flight is the dominant mode of transportation, made possible by Claudia Fluid: a liquidized form of the crystals that are produced on the planet. An organization known solely as "the Guild" has absolute authority over the skies, with a monopoly on the engines that make use of this fluid. Moreover, as ecological disasters destabilize the warring countries of Anatoray and Disith, the Guild also arbitrates in the disputes between the two. Caught in the middle of the conflict are Sky Couriers, piloting small, two-person vanships that fly freely through the sky. Last Exile follows the adventures of two teenagers who dream of surpassing their parents: Claus Valca, son of a famous vanship pilot, and Lavie Head, Claus' best friend and navigator. Their job as couriers entails passing through an air current called the Grand Stream that separates the hostile nations, which even standard airships struggle to survive. However, when they take on a high-rated delivery to bring an orphan girl named Alvis Hamilton to the battleship Silvana, they get dragged into a much greater conflict that pits them against the might of the Guild. [Written by MAL Rewrite]

Having narrowly avoided the collision with the asteroid, the Sidonia sets a course for the Lem system in order to wipe out the Gauna nest.