With the rise of technology, human settlements expanded across the solar system, from Mercury to Pluto. This progress sparked the creation of the "Daiundoukai," a massive athletic event featuring young women from every corner of the solar system. The winner is crowned "Cosmo Beauty" and receives a status akin to royalty.
Kanata Akehoshi, once a young potato farmer, spotted what seemed like a meteor falling into a nearby forest. Investigating, she discovered a crashed spaceship with a weakened girl inside. The girl gave Kanata two wristbands and asked her to enter the Daiundoukai and claim the title of Cosmo Beauty. Kanata agreed, but the girl vanished without revealing her identity, leaving no evidence. From that moment, Kanata dedicated herself to intense training to fulfill her promise.
After qualifying to represent Earth, Kanata arrives at the University Satellite, where she and other hopefuls prepare for the tournament. She builds friendships with fellow competitors, encouraging teamwork to sharpen their competitive skills. As Kanata advances toward the prestigious title, her chances of meeting the mysterious girl grow, leading her to uncover a hidden truth about the Daiundoukai.