During a fateful childhood meeting, Mira Kinohata encountered a stargazing dreamer named Ao Manaka. Although their time together was brief, Ao introduced Mira to the marvels of astronomy, ranging from orbiting planets to distant stars. Before they parted ways, Mira discovered that a star bearing her name exists, whereas none exist for Ao. Consequently, she made a vow: one day, she would discover a new asteroid and name it after Ao. Years later, Mira remains fascinated by astronomy. Now a high school student at Hoshizaki Academy, she attempts to join the Astronomy Club. Unfortunately, she learns that the club has been merged with the Geology Club to create a single Earth Sciences Club. She joins this new club and encounters a pleasant surprise—she reunites with Ao after years of separation. Together with their new clubmates, Mira and Ao embark on a journey to fulfill their promise. How difficult could it possibly be to find an asteroid?