Errol Flynn stars in this spy drama as Mountie Steve Wagner, who tracks downed Nazi flyer Hugo von Keller through the Canadian wilderness. When Wagner and fellow mountie Jim Austin catch up with Von Keller, they pretend to be on his side, hoping that he'll reveal his espionage plans. Taken in, Von Keller leads the mounties towards a secret Nazi hideaway, where the Germans have hidden a huge bombing plane to be used against North America. The fact that Wagner is posing as a Nazi sympathizer hardly endears him to Von Keller's hostage, Laura McBain, but when the truth is revealed she professes her love for him.