The man he knew as "Control" is dead, and the young Turks who forced him out now run the Circus. But George Smiley isn't quite ready for retirement—especially when a desperate Russian woman defector surfaces with a shocking accusation: a Soviet mole has penetrated the highest level of British Intelligence. His treachery has already blown some of their vital operations and their best networks. He is one of their own kind. But which one? Relying only on his wits and a small, loyal cadre, Smiley traces the breach back to Karla—his Moscow Centre nemesis—and sets a trap to catch the traitor.