The first game of the video game series. Cosmo's journey begins as she takes on The Metarex.
One day, Dark Oak (the main villain of Sonic X Season 3) interduces that they have to destroy the planet, but first needs the energy of a species known to that. Seeing Cosmo's home planet, The Metarex travel towards The Seedrian Star Galaxy, the home of the Seedrian.
The Following day, Cosmo goes flowers the plants of her garden as Galaxina comes up to her saying that mother needs her as she is having an important meeting. Cosmo goes with her sister as to the meeting, as Earthia introduces her