An American doughboy, stationed in France during the Great War, goes on a daring mission behind enemy lines and becomes a hero.

Hamilton Hill meets Estelle Redding in an umbrella repair shop and rescues her from two thugs soon afterwards. Estelle has hidden in the handle of her grey parasol the formula for "Coalex," an inexpensive substitute for coal which the coal trust is trying to prevent from reaching the market. Edward Burnham, one of the thugs, tells Hamilton that Estelle is a German agent, but the infatuated young bachelor fails to believe the story.