Somewhere in France

Marie Chaumontel, a spy for the Germans during World War I, vamps her way through the French high command, accumulating state secrets as she discards lovers. Captain Henry Ravignac commits suicide because of her, after which his brother, Lieutenant Charles Ravignac, vows revenge. As a result, he pretends to be a German spy and then becomes an assistant to Marie, all the while gathering evidence against her. Finally, he accumulates enough to hand her over to French authorities, after which he is hailed as a hero for so damaging German espionage operations.