Written by Derrick Sherwin
Story by Kit Pedler
Directed by Douglas Camfield
Narrowly evading a missile fired at them from a spaceship in Earth's orbit, the TARDIS materializes in England of the near future. Discovering that the TARDIS is damaged, the travellers attempt to reach their old friend Prof. Travers for help. However, upon reaching Travers' home they encounter Isobel Watkins, who lets them know that Travers is away and she and her uncle Professor Watkins, are living there temporarily. Isobel is concerned as her uncle has recently gone missing. The Doctor offers to help track him down, starting at this work-place, the London HQ of International Electromatics, the world's major supplier of electronic equipment.
Meeting IE's managing director Tobias Vaughn, the Doctor is immediately suspicious. Soon after, the Doctor and his friends encounter old ally Colonel Lethbridge-Stewart, now promoted to Brigadier and in charge of the British branch of the United Nations Intelligence Taskforce (UNIT). UNIT is investigating a series of odd disappearances that seem to be connected to International Electromatics. The Brigadier asks the Doctor to help him in his investigation.
The Doctor discovers that Vaughn is working with the Cybermen in a plan to invade Earth, though Vaughn's try aim is to betray them and seize control for himself. Professor Watkins is being forced by Vaughn to develop a machine that will generate emotional impulses in the Cybermen, a process that causes the cybernetic beings to die or go insane.
Using a hypnotic signal broadcast through IE equipment and products, the Cybermen immobilize most of Earth's population. However, the Doctor has managed to protect himself and UNIT from the signal and they mount a counterattack, with the reluctant aid of Vaughn himself. Together, they successfully fight off the invasion.
A pilot for the new direction the series was about to take, The Invasion is slick, action-packed and well made. All things you'd expect from the superb Douglas Camfield. The story is definitely over-long, the result of the continuing chaos behind-the-scenes which saw scripts fall through. Still, Sherwin and Pedler provide a solid adventure tale, albeit one that owes more to James Bond than science fiction.
The Invasion is arguably the best story to feature the Cybermen, ironic given that they barely appear in the story and rarely speak once they do. They are instead represented by the Cyber Planner, who is co-leading this invasion with one of Doctor Who’s most charismatic and complex villains, the wonderful Tobias Vaughn (Kevin Stoney). Vaughn is a treat to watch; arrogant, smooth, charming, witty, unbalanced and utterly convinced of his own supremacy. His scenes with the Doctor positively crackle, and it’s clear that Troughton and Stoney loved playing off each other. but their chemistry is secondary to the wonderful relationship Vaughan has with his second in command and toady, Packer. Peter Halliday gives a superb performance, making Packer somehow hilariously inept but still terrifyingly brutal. Watching him melt down over the course of the serial is great, and his borderline hysteria is a great contrast to Stoney's sly, unpredictable and cunning Vaughn. Of course, it's always wonderful to have Nicholas Courtney turn up, and by this point the Brig is firmly established and on his way to the fan favourite he would become.
It's certainly not the most challenging or innovative story, to be sure, but it does settle the question as to whether Doctor Who could work in an earth-bound, action-oriented, contemporary setting. It hits all the notes it tries for, generating thrills aplenty and if the Cybermen are reduced to little more than thuggish invaders, at least it's in a story that is this much fun.