In exchange for political asylum, Polish defector Leiser (Jones) agrees to return behind the Iron Curtain to confirm the suspicions of the British Security Chief that East Germany is building a rocket in violation of the disarmament pact. Once in East Berlin, Leiser falls in love with a beautiful young girl and the couple decide to flee the espionage experts - both East and West - to start a new life together. But they soon find themselves pawns in the brutal game where the stakes are human lives. Adapted from the classic John Le Carre spy novel.