After being asked to come out of retirement to settle the affairs of a close friend, George Smiley searches out his old organization, the Circus, which has now become so overwhelmed by political considerations that it doesn't want to know what is really happening. George begins to follow up on the clues of his friend's past days, discovering that the clues lead to a high person in the Russian Secret service, and a secret important enough to kill for. George continues to put together the pieces a step ahead or a step behind the Russian killers.