British Army officer John Carshalton is serving in Canada when he gets into a battle with a Frenchman over the affections of a woman. The dispute ends with Carshalton killing his rival in an illegal duel, and he must flee south of the border to escape court martial. He finds himself in a small Kansas town near Abilene, where he makes a victorious stand with an ageing deputy sheriff against a group of outlaws. But the murdered Frenchman's brother is after him, intent on forcing him into one more duel...