Mr George Smiley is small, podgy, and at best, middle-aged. He is disillusioned, wrestles with idleness, and has been deserted by his beautiful wife. He is also compassionate, ruthless, and a senior British intelligence officer in short-lived retirement from the Circus, the British Secret Service organisation situated in London. But Moscow centre has infiltrated a mole into the Circus, and it's more than likely the perpetrator is Karla, Smiley's old adversary and his opposite number in Moscow. And when, at the dead of night, a member of the Cabinet offers Smiley the job to 'clean the stable, do whatever is necessary', it becomes a long and bitter battle of wits between Smiley, the master of deceit, and the enigmatic Karla.