Katsumi Kunimasa, a skilled baseball player, spent years disguised as a boy to compete. Her true identity was uncovered by an old family friend who scouted her for professional play. This led her to join the Chunchi Dragons, a team owned by her father, pitting her against his coached team in a central conflict.

On the Dragons, she formed a significant friendship with the catcher, Oikawa. Through her exceptional pitching skills and performance, she gradually overcame initial skepticism and resistance from teammates and the baseball community.

Her background includes starring on a student squad that won a summer tournament, attracting the scout's attention. As the Dragons' star pitcher, she led them to victory in the national championships at Koshien Stadium within a year, marking the culmination of her competitive arc.

Her entire story, including her background, conflicts, relationships, and development, is contained within the original OVA release.