Paris 1917 during the First World War: Dutch-born Margaretha Zelle, who earns her living as an erotic nude dancer in Parisian cabarets under her stage name Mata Hari, is commissioned by the German secret service to seduce and spy on the French captain Francoise Lasalle. She also manages to send secret documents that François is carrying to a contact overnight. However, when she falls in love with François, she only accepts the next assignment under pressure. Her clients, however, know about her liaison with François. She is threatened that something will happen to François if she refuses to work with the Germans in the future. All she has to do now is steal the plans of a French ammunition depot from a safe.