The Secret Game(1917)

In the office of Major Northfield, the quartermaster of the Pacific Coast, a leak has been discovered which may endanger the safety of American transports that are secretly carrying troops across the Pacific. Nara-Nara, a Japanese detective, is assigned to the case because his country has guaranteed safety to these transport ships. Nara-Nara believes that Northfield is guilty, although in reality it is Northfield's secretary Kitty Little, a girl of German ancestry, who is passing information to Dr. Ebell Smith, a German agent. Nara-Nara falls in love with Kitty, but soon after discovers that she is the leak in the quartermaster's office.