Kurosu Gen was once a rising star in the Japanese motocross B-League, winning his first three races before disappearing to train in the United States. Months later, he returns to Japan and makes a dramatic appearance at Asama Circuit during the victory ceremony of the Red Army, the most dominant works team in the nation. Before a crowd of seventy thousand spectators, he declares war on the team that has achieved an undefeated record of one hundred fifty wins in a single year. Dismissed as a foolish Don Quixote for his seemingly hopeless challenge, Gen is a privateer who rides without factory support, driven by the memory of his older brother, a former Japanese Motocross Grand Prix champion who died in a training accident when Gen was young.

The story is set within the competitive world of professional motocross in early 1980s Japan, where four major works teams—identified by their colors: Red Army, Yellow Tigers, White Fox, and Green Monsters—fight for supremacy. The Red Army, with its ruthless leader Shirono Munemitsu at the helm as president, stands above all others. Munemitsu is cold and pragmatic, willing to accept even those who have defeated his own son as long as they strengthen the team. The Red Army’s strongest rider is designated a Warrior and receives full team backing. Gen’s primary rival is Igarashi Shunichi, a Red Army Warrior known as the Water Assassin for his lethal riding technique that exploits water hazards to cut down opponents from behind. Igarashi is a massive, powerful rider whose aggressive style physically attacks competitors during races. Shirono Reika, Munemitsu’s daughter, opposes her father’s methods after how he treated her brother and becomes Gen’s supporter, proving herself capable by handling large motorcycles and even physically knocking Gen down with a punch.

After infiltrating a Red Army selection race, Gen witnesses Igarashi’s deadly techniques firsthand, recognizes his strength, and develops a fierce competitive drive. When the International A-Class Japanese Motocross Grand Prix opening race arrives, the other works teams unite to eliminate both Gen and Igarashi. Forced into an uneasy alliance, the two riders cooperate to defeat the opposing teams before finally facing each other in a one-on-one battle to determine who is truly the strongest. The narrative arc follows Gen’s rise from the B-League to the A-League, his confrontation with the established hierarchy of the works teams, and his personal rivalry with Igarashi—a clash between the lone privateer and the champion of the dominant faction, both ultimately respecting each other’s abilities as they settle their duel on the track.