Three Faces East (1926)

An English aviator who is taken prisoner during the war is nursed by a woman who bears a German name but in reality is a British intelligence bureau operative. He falls in love with her. She gees to England and is commissioned to investigate the activities of a spy, with whom she is soon in love. Her love of her country prevents her marrying him, however, and the aviator, also returned to England, is told she will wed him.