Kenji Hatano, ne supportant plus les sports en équipe, décide de se tourner vers l'hydroboat, une discipline qu'il va apprendre dans une école professionnelle. Autrefois très bon joueur de baseball, Kenji semble se trouver ici aussi un talent. Il se promet alors d'apprendre la technique du "Monkey Turn" et de devenir, d'ici 3 ans, l'un des meilleurs pilotes d'hydroboat de tout le Japon.

Kenji Hatano originally wanted to be a Baseball superstar, but didn't like how one player's mistake can hurt the whole team. Upon being shown a kyotei (hydroboat) race by his Principal and seeing a special turn called a Monkey Turn, he decides to try it out. After capsizing due to a Monkey Turn gone wrong, Kenji decides to become a professional Kyotei racer. Two years later, he graduates from the Yamato Training School and promises his friend Sumi Ubukata that he'll become Japan's No. 1 Kyotei racer within three years.