In 1943, as World War II rages on and threatens to shut down Major League Baseball due to the draft, a candy magnate and Chicago Cubs owner comes up with a plan to keep baseball alive: he creates a women's league. The All-American Girls Professional Baseball League (AAGPBL) is born, and scouts are sent across the country to recruit talented players. Sisters Dottie Hinson and Kit Keller, who work on a dairy farm in Oregon, catch the eye of a scout and are soon recruited for the league. Dottie's exceptional skills and Kit's fierce pitching quickly land them spots on the same team, the Rockford Peaches. However, Kit lives in her sister's shadow and grapples with fierce sibling rivalry.

As the newly formed league tries to gain a foothold in the public's consciousness, the Peaches and their teammates must not only play to win but also battle sexism, professional skepticism, and their own personal conflicts. The team's coach, a washed-up, alcoholic former ballplayer, is initially indifferent to the women's league and skeptical of its potential success. However, as the season progresses, he develops a grudging respect for the talent and determination of the players, even as he contends with his own personal demons. The women not only have to prove their worth on the diamond but also must adhere to strict rules of conduct and femininity, which chafes against their love of the game and individual identities.