Jun Kuramochi captains Aonagi University's aviation club, piloting gliders with notable skill. He recruits Tamaki Tsuru after she accidentally damages club equipment, seeing her potential despite other members' objections. To ensure her continued involvement, he deliberately withholds that the damaged glider was insured, letting her work off repair costs through club activities. His mentorship hones her natural flying abilities, recognizing her cockpit aptitude even as she struggles with aviation theory.

His leadership extends to guiding the club in national gliding competitions, viewing them as vital for securing operational funding. His aviation path grows complicated by financial ties to sponsor Yō Asahina, who previously purchased the damaged glider. This obligation pressures him into reluctantly accepting a professional racing offer in Germany, removing him from the university club during a critical period.

While competing in Germany, he survives a plane crash that temporarily severs contact with his team. After recovering, he rushes to reunite with Tamaki upon spotting her glider in the sky. Their emotional reunion culminates in her declaration about flying together indefinitely, which he interprets as potentially carrying romantic implications.

His interactions reveal further dimensions: he maintains a respectful rivalry with Hannan University's pilot Kaede Hatori, facilitates reconciliation between Tamaki and her estranged stepsister Chizuru Yano during a joint camp, and navigates persistent tensions with fellow club member Daisuke Sorachi over club management and training approaches. Throughout, he demonstrates a reserved demeanor balanced by commitment to aviation and his club members' development.