When World War I breaks out, brothers Roy and Monte Rutledge, each attending Oxford university, enlist with the Royal Flying Corps.

Rocky and Dan, war buddies, are prowl car cops on night duty. Dan is a cynic who views all lawbreakers as scum; Rocky feels more lenient. Both are attracted to the radio voice of communicator Kate Mallory; but in person, Kate proves reluctant to get involved with men who just might stop a bullet. By lucky chance, Rocky and Dan cause big trouble for murderous racketeer Ritchie Garris; but when he swears vengeance, Kate's fears may prove justified.