In 1988, Dottie Hinson attends the opening of the All-American Girls Professional Baseball League exhibit at the Baseball Hall of Fame. She sees many former teammates and friends playing a game, prompting a flashback to 1943.

With World War II threatening to shut down Major League Baseball (MLB), Chicago Cubs owner Walter Harvey persuades his fellow owners to bankroll a women's league. Ira Lowenstein is put in charge. Scout Ernie Capadino attends an industrial-league softball game in Oregon and likes what he sees in Dottie, the catcher for a local dairy. She is not interested and is happy with her life, waiting for her husband Bob to return from the war. Her younger sister, Kit Keller, however, is desperate to escape and make something of herself. Capadino is unimpressed by Kit's batting and refuses to watch her pitch but agrees to take her along if she changes Dottie's mind. Dottie agrees for her sister's sake.