U.S. Marines sergeants Flagg (Victor McLaglen) and Quirt (Edmund Lowe) have been bitter rivals for years, but when Flagg is promoted to captain and Quirt is assigned to his unit as his senior non-commissioned officer, their competition flares anew. Assigned to the front lines in France during World War I, Quirt and Flagg tussle over the lovely young Charmaine de la Cognac (Dolores del Río), daughter of local innkeeper Cognac Pete (William V. Mong).