Berlin, 1942.
Clara Vine, the Anglo-German actress, is working undercover in Germany as an agent of British intelligence. During a hiatus in the filming of Goebbels' latest propaganda film, the Sinking of the Titanic, she is covertly approached and asked to track down an errant British spy called Victor Stern.
Stern is a physicist, feared to be passing vital secrets to the enemy. He also happens to be Clara's former lover, who she met in Vienna at the home of the actress, Hedy Lamarr.
As Clara hunts for Stern, however, she finds herself the subject of a blackmail plot from a young woman at the Propaganda ministry, Gisela Vogel, who knows of Clara's Jewish heritage.
She faces a race against time to find the missing agent before Goebbels learns of her true identity.
Clara's search takes her to Hamburg and a meeting with the Third Reich's favourite astrologer, who foretells dramatic news about her future.
But even if Clara finds her former lover, does she have it within herself to kill him?
