In January 1963, British journalist Leo Cauffield mysteriously vanishes from his Beirut residence. His wife Sally was aware that he worked part-time for British intelligence, but was unprepared for the British embassy to inform her that they suspected he had defected to Communist Russia. As his wife pieces together the puzzling jigsaw puzzle of her husband's background, she follows her intense connection with him and his history as the head of MI6's counter-espionage section. Her tireless pursuit for the truth brings her to London, New York, and finally Moscow.