In Russia shortly before the outbreak of the First World War, Princess Vorontsov (Ellen Richter) is in love with a high-ranking officer of the tsarist army. When he is murdered, she craves revenge. The leading suspect is a lawyer with ties to nihilist revolutionaries. On behalf of the secret police, she travels to Switzerland in order to gain his trust and facilitate his arrest. Too late she realizes that she has been toyed with all along. Her fiancé was not the man she thought she was.