Takao Taniguchi starts as a timid substitute player on the second baseball team at prestigious Aoba Gakuin Junior High. Transferring to Sumiya 2 Junior High in downtown Tokyo unexpectedly propels him into the role of team captain. This demands significant personal growth as he leads the team through dedicated training and development. Under his leadership, they prepare for crucial matches, culminating in a regional preliminary final against his former school, Aoba Gakuin, demonstrating his perseverance in building the team's capabilities despite initial limitations.

Taniguchi continues as captain at Sumiya High School, striving to reach the national Koshien tournament. Following a prolonged defeat in the qualifying round semi-finals, he faces uncertainty about his future. After graduation, he delays college entrance exams to accept a paid position as Sumiya High School's baseball director. He remains actively involved, participating directly in team practices, including hitting balls during fielding drills.

As director, Taniguchi collaborates with the high school captain, Marui, implementing strategic improvements like weight training and enhanced nutritional support. He leverages connections with local business owners to secure discounted bulk rice for the team. His mentorship extends to new players such as Kondou Shigekazu, who joins Sumiya High inspired by Taniguchi's legacy. Taniguchi also navigates off-field relationships, including friendships formed at prep school that introduce light romantic subplots.

His influence endures as a symbol of perseverance for successive captains, emphasizing the importance of legacy. Kondou Shigekazu learns the concept of "legacy" directly from Taniguchi's guidance, illustrating how Taniguchi’s leadership philosophy continues to shape the team's ethos long after his playing years.