Haruki, a responsible high school student, finds himself instantly drawn to a captivating girl he encounters on a train. Her presence sparks something within him and he becomes determined to get to know her on a deeper level. As he observes her signing up for an astronomy club, a subject close to his heart, Haruki sees an opportunity to connect with her in a meaningful way.

Driven by a genuine interest in the girl, Haruki decides to join the astronomy club, hoping to spend more time with her. Despite the demands of his busy schedule, which includes caring for his younger siblings in the absence of their parents, Haruki's desire to explore the depths of their budding romance propels him forward. However, the romance he has veen looking for may not be the one he'd expected.