The story follows Kei, a 17-year-old motocross racer who has loved the sport since childhood. Just before a major Supercross race, his older brother, Kazuto Kazamatsuri (nicknamed "Aniki"), crashes mid-race and is fatally crushed by a falling motorcycle. Despite this tragedy, Kei continues to train hard and earns the right to compete in Supercross. However, his relentless pursuit pushes his body to the limit, and he suffers a severe spinal injury. Now, Kei must face off against the fastest riders in the world. Will the young Japanese racer, Kei Ichimonji (一文字慧), achieve the title of the world's best motocross rider?