A young woman disguises herself as a man and follows her fiancéé into the trenches during World War I to find out what war is really like.

Small-town social leader Joan Morant, who holds herself aloof from the "common people," is thrilled when wartime activity strikes her community; enlisting the support of her uncle, a congressman, she obtains an assignment overseas. Although she loves Reggie, a wealthy sheik, Joan plays with the affections of local garage-owner Tom Pike, both of whom she meets in France. Tom, transformed by his war experiences, rebuffs Joan's advances, and she seeks out Reggie, who is living his accustomed life of luxury as a supply sergeant. Joan's female companions, constantly making great sacrifices, impress upon her the seriousness of purpose in her work, and she resolves to do her part. When Reggie, called to the front, becomes hopelessly drunk, she dons his uniform and replaces him in the ranks, where she experiences a new admiration and love for Tom, her commander. Proving her heroism in battle, she returns to Tom, worthy of his love.