On her very first day at Satogahama Municipal High School, Arihara Tsubasa steps onto the stage while the school's clubs are being introduced and declares, "The girls' hardball baseball team is looking for members!" Since it was originally a girls-only school, Satogahama doesn't even have a baseball team for boys. Tsubasa is scolded for making this declaration about a club that doesn't exist, but at her homeroom teacher's suggestion, she decides to start an association. Later, Nozaki Yuuki, a new student who can't decide which club to join, runs into Ukita Akane, who says she's looking for the girls' baseball club...