In the second episode of the four-part story "Terror of the Zygons," several North Sea oil rigs have been destroyed, and the main suspect is none other than the Loch Ness Monster. But in the course of his investigation, the Doctor (Tom Baker) finds a spacecraft hidden in the depths of the Loch. It turns out that "Nessie" has been blamed for the skulduggery of a warmongering alien race called the Zygons. First shown on September 6, 1975, "Terror of the Zygons, Episode 2" was written by Robert Banks Stewart. ~ Hal Erickson, Rovi