Based on

Movies like A Foreign Spy (1913)

The army engineer and his daughter are deeply interested in each other, but, of course, the will of the father predominates. As a result the girl experiences many heart aches, because it does seem as though she is about to lose her sweetheart because he is not an army man. The issue is brought to a climax by the presence of a spy in the father's home. Plans for the border fortifications are stolen and the impending disgrace and ruin drive the officer to the verge of despair, from which he is rescued by the daughter and her sweetheart, who rescue the plans, and apprehend the spy.