Henri Tailleur is facing the biggest case of his career. Together with the star lawyer Eduart Clunet, he is defending the famous spy Mata Hari. For the French, the guilt of the femme fatale is already established. In order to make the impossible possible and exonerate his client, Tailleur decides to travel to Germany. He hopes to find evidence of her innocence in Berlin. It is a risky endeavor, as both nations are fiercely opposed to each other in World War I. And he doesn't have much time before the trial begins.