With the declaration of war, Jim Baker and Jersey, his coworker, who are working on a bridge construction job in Wyoming, join the Army and are sent to France with the Engineer Corps.  Patricia Hunter, an American society girl in the Ambulance Corps, impatient with the routine of her job, goes A.W.O.L. and wanders into the territory held by Jim's company; he rescues her from enemy shellfire and reprimands her.

At a rest camp they see much of each other, fall in love, and are secretly married.  Later, when Jim is recalled to the front and she is about to be court-martialed for her absence, she reads of his death.  To drown her misery, she opens the family chateau to entertain servicemen.  Jim, only wounded, is sent to the hospital and misconstrues her gaiety; he tries to persuade her to return with him to Wyoming, and when she refuses, he returns to the front.  On the day of the Armistice, however, he finds her waiting for him in the town where they were married.