In 1925 (year 14 of the Taisho 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.
The novels are set in 1925 when two 14-year-old Japanese high school girls named Koume and Shōko decide to start a baseball team in Japan where few baseball teams — male or female — exist at the time. First though, the two girls have no clue where to find nine players, how to use the equipment, and what even the rules are.