In 1914, the beautiful exotic dancer Mata Hari becomes a spy for Germany. By order of a certain Ludovic she lures François Lassalle home to steal valuable documents which he holds. Mata Hari succeeds but she ends up falling in love with the officer. A new mission is assigned to her. François who is desperately jealous breaks up with her. Mata Hari, first seeks refuge in Spain then returns to France in the hope of finding him ... Ambushed by the German patrol, François is killed. Mata Hari, betrayed by the Germans themselves, is shot in the ditches of Vincennes.