Russian spy Tania Fedorova (Greta Garbo) uses her seductive charms to steal precious secrets for the motherland. Few saboteurs can compete with her skills, as her handler, Gen. Boris Alexandroff (Gustav von Seyffertitz), knows well. But Tania's career in espionage is jeopardized when she meets a handsome Austrian, Capt. Karl von Raden (Conrad Nagel), who's also her latest target. Will Tania sever her ties with her country, not to mention risk Alexandroff's wrath, in the name of love?