In Uganda, a young girl named Phiona lives with her mother and siblings in the impoverished slum of Katwe. Struggling with day-to-day survival, Phiona's life changes when she meets Robert Katende, a missionary who teaches children how to play chess. Intrigued by the game, Phiona quickly demonstrates an extraordinary aptitude for chess, despite facing significant adversity and lack of formal education. Katende encourages her to pursue chess more seriously, and she begins to participate in local competitions, where her talent becomes evident to everyone.

As Phiona's skill grows, she starts to compete in prestigious tournaments, proving herself against more experienced players. The journey is not without challenges, as she must navigate societal pressures, financial constraints, and her mother's initial reluctance to support an unconventional dream. Nevertheless, Phiona’s passion for chess and her determination to change her family's circumstances drive her forward, offering a glimmer of hope for a better future. Along the way, the support from her coach and community plays a critical role in her development both as a player and a person.