While on a ship to Skagway, Alaska, Duke and Chester find a map to a secret gold mine, which had been 'stolen' by thugs. In Alaska to recover her father's map, Sal Van Hoyden falls in with Ace Larson, who secretly wants to steal the gold mine for himself. Duke, Chester, the thugs, Ace and his henchman chase each other all over the countryside—for the map.
Having been discharged from the Marines for a hayfever condition before ever seeing action, Woodrow Lafayette Pershing Truesmith delays the return to his hometown, feeling that he is a failure. While in a moment of melancholy, he meets up with a group of Marines who befriend him and encourage him to return home to his mother by fabricating a story that he was wounded in battle with honorable discharge.