Pearl of the Army (1916)

Episode 1: "The Traitor" Captain Ralph Payne is chosen to convey to the Major General at Panama a document of vital importance which discloses a weakness in our canal defenses by which a monarchy (hitherto overlooked by the United States) plots to overcome this nation. The document is secreted beneath his left shoulder strap, it first being prepared with invisible ink. From that time Payne finds himself the victim of a queer being that, through a strange medium, juggles with his good name and martial standing. At his apartment he finds a letter in handwriting the exact counterpart of his own and in it the startling contents: "The left shoulder strap and the locket reveal the secret; take the tip in time." Bewildered, he consults his chief, Colonel Dare, who instructs him to attend the Embassy ball that night as though nothing had happened, promising added secret service protection. In the midst of the evening's festivities, Payne and Pearl Dare find a secluded spot in the conservatory. Encouraged by a responsive light in her eyes, Payne is about to ask for her "yes" to the question that means happiness to him, when a messenger orders him to report to Colonel Dare at once. There he is informed that the Grenadian Ambassador has been murdered and in his lifeless hand a message found to Payne thanking him for services rendered Grenada. When Payne is searched the left shoulder strap reveals nothing hut a worthless piece of paper. In a daze he hears the order given to arrest him on a charge of treason.