Humanity progressively colonized the whole solar system as technology evolved, inhabiting planetary facilities from Mercury to Pluto. This results in the "Daiundoukai," a large-scale sports event in which various aspiring female athletes from all across the solar system participate. The competition winner is crowned "Cosmo Beauty," gaining queenlike status. Kanata Akehoshi, a retiring potato farmer, was a youngster when she observed a meteor-like object descend from the sky and smash into a neighboring forest. When she arrived to check the debris, she discovered a damaged spaceship and a girl who appeared to have been in it and had been debilitated by the crash. Kanata was given two wristbands, along with a request that she join the Daiundoukai and become the Cosmo Beauty.