Joan Mason, an enthusiastic motor girl, and Valerie Warde, a society debutante, meet at an automobile show. Next day they go together to the Motor Corps headquarters and in due time are accepted and become members of the Corps, in the service of the United States. The two girl drivers find motoring for Uncle Sam a most exciting business. Incidentally they are instrumental in rendering valuable service to the United States government by discovering and running down a secret organization of its enemies.