Doctor Who/Recap/S6/E03 The Invasion

Not pictured: Horrifiying noise by courtesy of The Great Old Ones' grandfathers.

You're an evil man, Vaughn. You're sadistic. You're a megalomaniac. You're insane. I pity you. But if I get half a chance, I'll kill you.

—Professor Watkins tells it like it is.

The TARDIS arrives in London in the near future, the Doctor and companions are enlisted by Isobel Watkins to find her father, a computer scientist working for International Electromatics.

IE's director, Tobias Vaughn, arouses the Doctor's suspicions - confirmed by meeting Lethbridge-Stewart again (see "The Web of Fear"), recently promoted to Brigadier, who says that numerous other IE staff have gone missing. Lethbridge-Stewart now heads the British arm of UNIT, the United Nations Intelligence Taskforce, charged with investigating alien sightings and other such things.

The Doctor discovers that Vaughn is acting on behalf of the Cybermen, who plan to invade Earth, but is also planning to double-cross them and seize power for himself. The Cybermen send a hypnotic signal through all IE-made equipment, immobilising most of Earth's population, and start emerging from London's sewers to take over. However, the Doctor has managed to protect himself and the others from the signal and succeeds in defeating the invasion, thanks in no small part to Zoe's phenomenal brain, plotting guidance trajectories for nuclear missiles to destroy the incoming fleet.

The Invasion presaged the shape of many Doctor Who stories to come, featuring an alien invasion of Earth aided and abetted by a corrupt industrialist, with UNIT providing cannon fodder and the military connections to fight back.

All episodes including animated reconstructions of the first and fourth can be viewed here.

Tropes

Animated Adaptation: The two missing episodes were remade in an animated format for the DVD release.
Corrupt Corporate Executive
Cut and Paste Environments: The same set is used for Vaughn's office in two different buildings (with a different view out of the window). Lampshaded.
Evil Is Not a Toy
Expy: Professor Watkins and Isobel for Professor Travers and Anne, and possibly the sewer-lurking Cybermen for the subway-lurking Yeti—there's a rumour that this story was originally planned as a direct sequel to "The Web of Fear", before the writers of the two previous Yeti stories fell out with the showrunners over the editing of "The Dominators".
For Inconvenience Press One
Genre Savvy: Vaughn has prepared the emotion machine in the quite likely event the Cybermen will turn on him and even wants to take the TARDIS in the event that his deal with the obviously untrustworthy monsters goes south and he has to get away.
Getting Crap Past the Radar: Vaughn isn't exactly clear on what Packer will do to Isobel or Zoë if they're turned over to him, but it's as strongly implied as it can be in Doctor Who they'll be raped.
Idiot Ball: Zoe, mainly to annoy Jamie, agrees to Isobel's insanely dangerous plan of photographing the Cybermen. Unlike Isobel, she's encountered the Cybermen before and ought to know better.
Kidnapped Scientist: Professor Watkins.
Large Ham: Viewers may remember Kevin Stoney from his former role as Mavic Chen. His hamminess has seen no decrease whatsoever.
Magic Skirt: Well, kilt - the girls' skirts definitely don't do this, but Jamie's kilt stays in place. It's not magic, though - it's weighted.
Panty Shot: Lots of them, to an almost disturbing frequency; Zoe has eight, Isobel has four.
Rank Up: Colonel Lethbridge-Stewart is now The Brigadier.
Redemption Equals Death - Vaughn
Stock Episode Titles: 40 uses
Surrounded by Idiots: Vaughn has his incompetent henchman Packer—unusual given his stated desire for efficiency.
Talking The Computer To Death: Zoe!
Take Our Word for It - Partway through the story, the Doctor says that it's time that they rescued Professor Watkins. The very next shot features one of Vaughn's men describing in detail the incredible, action-packed rescue operation that UNIT carried out, yet we never got the chance to see (it was scripted, but there wasn't enough time to film it).
- Ian Marter, who wrote the novelisation of the story, admitted that he was tempted to play the scene for laughs and reveal that all that had really happened was that the Doctor distracted Watkins' guard for a few moments while Benton rescued the professor, with the whole "rescue operation" being made up by the guard in the vain hope that Vaughn wouldn't execute him for his failure. In the end though, Marter kept the scene as it had originally been written.
Twenty Minutes Into the Future
Uncanny Valley (In-Universe): The Doctor notices that Vaughn doesn't blink as often as a human should, a sign that he has a cyborg body.
Utopia Justifies the Means - Unlike most Corrupt Corporate Executives, Vaughn believes in a greater good that justifies what he's doing.
What Happened to the Mouse?: Whatever became of Rutledge?