Jack Johnson, the first African-American heavyweight boxing champion, plays himself in a sports-themed melodrama where Joe Walker (Reed Thomas), a "98-pound weakling" is forced to step up when his girlfriend, Molly Moran (Blanche Thompson) is falsely accused of grand larceny. Joe meets up with Johnson, who teaches him the manly art of self-defense as well as the sportsmanship and fair play to the point where Walker leads the black baseball team the Kansas City Monarchs to victory over the Detroit Stars (using the actual players), as well as discovering that his rival Tom Atkins (Walter Simpson) had framed his girlfriend, Molly Moran, whereupon he brings him to justice and frees her.