Subaru Hasegawa dreams of becoming an elite basketball superstar, but his plans are derailed when his school's basketball team suspends activities for a full year. Stunned by this development, he decides to step away from the sport entirely.
His aunt, Mihoshi Takamura, later asks him to coach the Keishin Academy girls’ basketball team, and he reluctantly accepts. There, he meets fifth graders Tomoka Minato, Maho Misawa, Airi Kashii, Hinata Hakamada, and Saki Nagatsuki. He begins training them with a single objective: to defeat every strong opponent they encounter.
Ro-Kyu-Bu! follows the journey of five elementary school girls and their coach as they refine their adorable approach to playing basketball.