"Keijo!!!!!!!!" is a sports anime centered around the fictional competitive sport of keijo, where female athletes compete on floating platforms to knock opponents into the water using only their hips and buttocks. The protagonist, Nozomi Kaminashi, is a former gymnast who enrolls in Setouchi Keijo Training School to pursue a career in keijo, driven by the promise of financial success. The series explores her journey as she trains, competes, and forms rivalries and friendships with other aspiring keijo players.

The narrative begins with Nozomi entering the competitive world of keijo, where she quickly demonstrates her natural talent and determination. Alongside her roommate, Sayaka Miyata, a shy but skilled swimmer, Nozomi navigates the rigorous training regimen and intense matches. The story introduces a variety of characters, each with unique abilities and backgrounds, such as Non Toyoguchi, a powerhouse with immense strength, and Mio Kusakai, a tactical genius. These characters contribute to the dynamic and strategic nature of the sport, showcasing different techniques and styles in their matches.

As the series progresses, Nozomi and her peers face increasingly challenging opponents, both within their school and from rival institutions. The competitions are structured around team battles and individual duels, emphasizing teamwork, strategy, and physical prowess. The anime highlights the physical and mental demands of keijo, blending humor, action, and moments of character development. Themes of perseverance, camaraderie, and self-improvement are woven into the narrative as the characters strive to master the sport and achieve their goals.

The plot builds toward major tournaments, where the stakes are heightened, and the characters' skills are put to the test. Through these events, Nozomi and her friends grow stronger, both as athletes and individuals, while confronting their own limitations and aspirations. The series concludes with a focus on the characters' continued pursuit of excellence in the world of keijo, leaving their futures open-ended but filled with potential.