In the fourth episode of the eight-part story "
The Invasion," the Doctor (
Patrick Troughton) and Jamie (Frazer Hines) are rescued from sinister electronics executive Tobias Vaughn (Kevin Stoney) by an old friend, Brigadier Lethbridge-Stewart (Nicholas Courtney). Now aligned with a group called U.N.I.T. (United Nations Intelligence Taskforce), the Brigadier elicits the Doctor's aid in preventing Vaughn from taking over the world. But the villain is equipped with an "army" of his own -- comprised of the Doctor's perennial enemies, the Cybermen. "The Invasion, Episode 4" was originally shown on November 23, 1968. ~ Hal Erickson, All Movie Guide