John Le Carre's government operative George Smiley (Alec Guinness) comes out of retirement again when a former colleague is murdered. Using his keen intuition and espionage expertise, Smiley fingers a Soviet arch-rival who goes by the name of "Karla," and an intense cat-and-mouse game ensues in this six-part follow-up to "Tinker, Tailor, Soldier, Spy."