In the conclusion of the six-part story "The Web of Fate," Col. Lethbridge-Stuart (Nicholas Courtney) has successfully driven back the invasion of the Yeti robots. Even so, the Great Intelligence persists in his scheme to conquer the world with his robot army. It falls to the Doctor (Patrick Troughton to try to foil the Intelligence, just as he'd done in the previous Dr. Who adventure "The Abominable Snowmen." Originally telecast March 9, 1968, "The Web of Fear, Episode 6" was written by Mervyn Haisman and Henry Lincoln; this episode apparently no longer exists.
by Hal Erickson synopsis