"Keijo" is a popular gambling sport where contestants stand on platforms floating in water and must use their butts and chests to battle each other, trying to push one another off the platform. Nozomi Kaminashi, a high school student, aspires to join the sport after graduation. Coming from a poor family, Nozomi hopes to earn a fortune by playing Keijo. She has trained in gymnastics, giving her excellent balance and flexibility. After high school, Nozomi enrolls in a training boarding school and steps into the world of Keijo.
