Keiichirō Asano is the main pitcher for Hodokubo High School's baseball team. He initially maintains distance from the team and attends regular training irregularly. This stems from unresolved clashes with the coach and his own stubborn, self-reliant personality that resists admitting weaknesses. His detachment is also rooted in being a former alumnus who rejoined the team but became disillusioned after a favorite teacher was dismissed over misconduct allegations.

During a critical match, Asano pushes himself beyond his physical and mental limits trying to single-handedly compensate for a defensive error by shortstop Yunosuke Sakurai, particularly after exceeding 100 pitches. This overexertion causes a noticeable decline in his pitching effectiveness and leads to failure. This experience forces him to confront his limitations and recognize baseball requires collective effort, not individual heroics.

Following this setback, and influenced by changes within the team fostered by manager Minami Kawashima applying management principles, Asano transforms significantly. He reconciles with his coach, who supports him during this period. He embraces responsibility towards his teammates and begins trusting their abilities. This shift leads him to embody the team's newly discovered spirit more fully than any other member.

Subsequently, Asano commits to rigorous training, intensely focusing on improving his technique, physical conditioning, and mental endurance to overcome his previous performance drop-off. He channels his determination into disciplined practice. Outside baseball, he finds relaxation and motivation listening to songs by singer Mari Tamagawa, especially during team travel to games.