"Asteroid in Love" centers on Mira Kinohata, a high school student passionate about astronomy, and Ao Manaka, her childhood friend who loves geology. The two reunite in high school after losing touch and join the Earth Science Club, a small group of students dedicated to exploring the natural sciences. The club, which also includes members like Mikage Sakurai, an enthusiastic upperclassman, and Inose, a reserved but knowledgeable student, embarks on various activities, including stargazing, rock collecting, and field trips, to deepen their understanding of the Earth and the cosmos.

The narrative intertwines Mira and Ao's personal growth with their shared goal of discovering a new asteroid, a dream they pledged to achieve as children. Their journey is marked by collaborative efforts, scientific curiosity, and the challenges of balancing their passions with everyday school life. The series highlights their friendship and the bonds they form with other club members, emphasizing teamwork and mutual support.

As the story progresses, the characters explore themes of perseverance, discovery, and the beauty of the natural world. The Earth Science Club's activities often serve as a backdrop for character development, with each member contributing their unique skills and perspectives. The series balances lighthearted moments with deeper reflections on the characters' aspirations and the significance of their shared experiences.

Through its focus on science and friendship, "Asteroid in Love" presents a heartfelt portrayal of high school life, blending educational elements with a slice-of-life narrative. The characters' dedication to their goals and their evolving relationships form the core of the story, creating a cohesive and engaging exploration of their journey together.