Gun Koma, a motorcycle racer straddling illicit street circuits and professional leagues, rises from underground racing roots as a high school rebel in Japan’s "rolling-zoku" scene. His reputation ignites after toppling a 750cc rival on a modified 50cc moped, a feat propelling him into pro racing under the mentorship of Miyuki Ichinose, daughter of a team president. His technical prowess shines through customized machines—a Honda CB750 and Suzuki GSX-R—each tweaked to mirror his aggressive yet precise style.

A fierce rivalry with Hideyoshi Hijiri, a Suzuki Katana rider, evolves into an uneasy alliance during Suzuka’s endurance race, testing their mutual respect. Bonds with mechanic Hiro Okita (Kawasaki Z400GP) and romantic partner Ai Itou anchor his personal journey, while echoes of loss tied to Tomoyo Hijiri’s fractured past add depth to his motivations.

Transitioning from mountain-pass daredevil to All Japan Road Race Championship contender, his arc blends rebellion with discipline. Spin-off games and a technical OVA spotlight his legacy, emphasizing race strategy and machine physics. The iconic number 56, emblazoned on his retro-styled helmet and ’80s-inspired gear, transcends fiction—real-world racer Shinya Nakano adopted it as tribute. Merchandise immortalizes his aesthetic: the bold "G" on his helmet, vintage leathers, and diecast replicas of his bikes cementing his cult status.