After jointly founding the so-called Space Club, Youichi and his friend Amamiya Ginga, the son of Amamiya Daigo, spent their school days building a rocket -- until one fateful night, a mysterious young girl called Aries crash-lands near them, her memories also lost from the shock of the landing.

After jointly founding the so-called Space Club, Youichi and his friend Amamiya Ginga, the son of Amamiya Daigo, spent their school days building a rocket -- until one fateful night, a mysterious young girl called Aries crash-lands near them, her memories also lost from the shock of the landing.