In a fateful childhood encounter, Mira Kinohata met a stargazing dreamer named Ao Manaka. Though their time together was short, Ao showed Mira the wonders of astronomy, from orbiting planets to distant stars. Before they parted, Mira learned that a star together with her name exists, but there are none with Ao’s. And so, she forged a promise: at some point , she would discover a replacement asteroid and name it after Ao.
Years later, Mira remains fascinated with astronomy. Now in highschool at Hoshizaki Academy, she tries to hitch the Astronomy Club. Unfortunately, she finds out that the club has been merged with the Geology Club to make one Earth Sciences Club. She joins this new club and finds a pleasing surprise she reunites with Ao after years of separation.
Alongside their new clubmates, Mira and Ao begin their journey together to satisfy their promise. How hard could it possibly be to seek out an asteroid?