Some say George Smiley is in innocent retirement. Others say he was sacked after the Czech scandal. But all agree that nobody ever leaves the 'Circus' without some unfinished business. Brought out of retirement to trace an enemy infiltrator in the department where he was once the prize employee, the shy and retiring master of espionage moves forwards to investigate and finds himself going backwards over very old ground.

Called out of retirement to settle the affairs of a friend, Smiley finds his old organization, the Circus, so overwhelmed by political considerations that it doesn't want to know what happened.

At the height of the Cold War, a precarious operation goes deadly wrong, and the head of British Intelligence wonders if a double agent is leaking vital secrets. Brought out of retirement to expose the potential mole, master spy George Smiley is the only one who can be trusted to expose one of their own. Or can he? As the emotional and physical tolls mount on the high-ranking suspects, Smiley will be forced into the ultimate international spy game...