Assistant to freight express agent Dave Haskell in the town of Pitt's Junction, Jim Kelly develops strong biceps lifting egg crates onto the daily train. Jim soon falls in love with Dave's lovely daughter Kitty, who, he worries, is interested in city slicker Perry Woods. When Woods steals $2,000 from the station safe, Jim, thinking that Dave took the money, confesses the crime and leaves for Chicago. He meets two fighters headed for a gym and, impressing them with his "egg crate wallop," lands a job as a training assistant. When Jim knocks out "Battling" Miller, who is about to throw a fight, Jim takes Miller's place against boxer "Young Howard," who is really Woods. After taking four rounds of brutal beatings, Jim connects in the fifth with his wallop and knocks out Woods. When a patched bill missing from the safe is found on Woods, Jim, now a hero, wins Kitty.