Susumu Karasawa, a former junior high judo champion, pivots to baseball at Seishū High after witnessing Nakao Yuri—the coach’s daughter—distraught over the team’s decline. Leveraging his judo-honed athleticism as a right fielder, he initially seeks to impress Yuri but gradually embraces baseball as a path to self-discovery and teamwork. His early antics showcase impulsiveness, like cheering a teammate’s dubious tactics instead of questioning them, yet these quirks mask a growing sense of accountability.

As challenges mount, Susumu confronts ethical lapses within the team, mediates a teammate’s familial rift by advocating for perseverance through sports, and battles a crippling batting slump that forces introspection. Parallel to his athletic journey, his dynamic with manga artist Takagi Youko evolves from being her comedic caricature subject to forging a tentative bond, complicating his emotional landscape.

Central to his growth is his camaraderie with Katsuya Niimi, blending loyalty with lighthearted rivalry. While initially a foil to Niimi’s romantic endeavors, Susumu’s maturation balances humor with resolve, culminating in pivotal contributions to the team’s Kōshien qualification. His arc traces a transition from comic relief to a layered figure navigating setbacks, relationships, and the weight of collective ambition.