Keiko Himuro, Chairman of the Kisuragi School, puts together an all-girl baseball team led by Ryo Hayakawa, daughter of a legendary pitcher, in hopes of proving that girls can compete just as well as boys. Their goal: Koshien stadium, where only the best teams get the opportunity to play.

In 1925 (year 14 of the Taishō period), after being told by a baseball player that women should become housewives instead of going to school, two 14-year-old Japanese high school girls named Koume and Akiko decide to start a baseball team in order to prove him wrong. During this time, when even running was considered too vulgar for women, baseball is known as "what the boys do" and they face many difficulties when searching members, getting permission from their parents and when learning about the sport itself.

Minami joins her High School baseball team as a team manager after finding out that her best friend Yuuki is in the hospital and can't be a team manager any more. In order to try to fill in for Yuuki and to help out the team the best she can, she goes out to find a book on how to manage a baseball team.

Unfortunately, she accidentally buys Peter Drucker's book called "Management: Tasks, Responsibilities, Practices" which is actually about how to properly manage a business. Because she couldn't return the book, she decides to read it anyway and to try to apply the business management concepts to the baseball team so that way they can go on and win the Nationals.