The stifling summer streets of Lisbon in 1944 are teeming with spies and informers when
Andrea Aspinall, an English mathematician turned spy, meets. Karl Voss, military attache at the German Legation. They attempt to find love in a world where no one can be believed. Voss is secretly working
against the Nazis so that atomic and rocket technology do not find their way
into Hitler's hands. After a night of terrible violence Andrea is left with a secret.
When, later in East Berlin at the time of the Cold War, Andrea discovers that the deepest secrets aren't held by governments but by those closest to you she is forced to make the final and the hardest choice.