translated from ebookjapan:

Elementary school student Kazamaki Shouta is often picked on because of his small stature and timid personality. He dreams of someday growing up and leaving his bullies in the dust. He happens to see a pocket bike race one day and was deeply moved that, despite the pocket bike's small size and most of the racers being children, the race was filled with surprising speed and intense effort. Even a small girl, Kana, was unafraid to assertively maneuver into first place.

After spotting Shouta watching intently, adult particpant Okita Takurou lets Shouta have a ride on his bike. Riding a motorcycle for the first time, speeding down the track amidst the practicing racers, ignites his passion for motorcycle racing. Through observation, he figures out how to lean through corners and other techniques, discovering that he has a natural talent for racing. Taking Takurou as his coach, and against his parents' wishes, Shouta starts to compete in races. This is the story of Shouta's journey as he aims to become a champion racer.