One summer day in her second year of high school, Aki sees her school's boys' baseball team playing in the Koshien (the National High School Baseball Championship), and unable to stand still, she sets her mind to start her own club. One day, Samejima, who used to play for the Japan University of Physical Education's women's softball team, comes to the school as a physical education teacher, and Aki goes to ask her to become the coach of the baseball team...