Craggy veteran boxing manager and trainer Frankie Dunn (CLINT EASTWOOD) has seen better days. Not only is his gym filled with mediocre to laughable boxers -- Shawrelle Berry (ANTHONY MACKIE) and Danger Barch (JAY BARUCHEL) respectively -- but his best fighter, Big Willie Little (MIKE COLTER), has just left him for a manager he believes won't keep holding him back from advancing to the big bouts.
To make matters worse, Maggie Fitzgerald (HILARY SWANK), a poor, thirty-something waitress, keeps pestering him to train her. Although his best friend and former boxer Eddie Scrap-Iron Dupris (MORGAN FREEMAN) -- who looks after Frankie's gym -- thinks he should give her a chance, the veteran initially refuses her repeated requests.
When she proves that she may have what it takes to be a champion, however, he eventually agrees to be her manager and trainer. With hopes that she'll eventually get to fight German champion Billie "The Blue Bear" (LUCIA RIJKER), Maggie trains hard and starts piling up many victories. Yet, with their respective personal issues with family and other matters, as well as an unexpected turn of events, the unlikely duo try to make the best of their situation.