Mayme walks out on her husband, Pete Palooka, after he wins the middleweight championship and shows his proclivity for life in the fast lane. She raises son Joe on a farm, by herself. When slippery fight manager Knobby Walsh happens to discover Joe's surprising punching power, he signs him. With current champion Al McSwatt needing an easy opponent, Walsh gets Joe the fight. Palooka steals the championship from McSwatt when McSwatt shows up for the fight drunk. Now it's Joe's turn to live in the fast lane, winning fights and drinking hard with vamp Nina. However, when McSwatt and his manager trick Joe into a rematch, it's time to test his real boxing talent.