The Cybermen surround the Doctor (David Tennant), Rose (Billie Piper), Mickey (Noel Clarke), and the Preachers. The Doctor overloads the Cybermen with the recharging power cell from the TARDIS, and they collapse. They escape with Rose’s father Pete (Shaun Dingwall) but her mother Jackie (Camille Coduri) is trapped inside the house. Of course, this is Rose’s parents in the parallel universe, where Rose was never born. Pete explains that he is the Preachers’ source of secret information on his boss, John Lumic (Roger Lloyd Pack), who is taking over the British government and creating Cybermen. Got it?

Actually, Pete thought he was in communication, not with a band of undercover brethren, but law enforcement. John Lumic is the law. From his Zeppelin, he activates the ubiquitous earpods and sends the people of London to the factory in Battersea Power Station to be converted into Cybermen. Our group of heroes arrive at the factory and find the Zeppelin (if it’s an alternate Earth, there are Zeppelins, always) moored nearby.

They are attacked by the Cybermen while trying to scale a fence and Rickey, Mickey’s parallel universe doppelganger, is killed. While Mickey and Jake try to board the Zeppelin and destroy the earpod transmitter, Pete and Rose try to find Jackie, and the Doctor and Mrs. Moore (Helen Griffin) try to find the way to Lumic. Pete and Rose are captured by the Cybermen and taken to Lumic. Jackie, who has been converted to a Cyberman, notices them. Mrs. Moore is killed, but the Doctor discovers that each Cyber unit contains an emotion inhibitor. If he disables the inhibitor signal, the Cybermen will realize what they have become and probably die of shock. But the Doctor is captured and taken before Lumic.

There, the Doctor learns that the Cybermen have converted Lumic to the Cyber Controller. Mickey and Jake disable the transmitter and the humans flee the factory. The Doctor tells Mickey to find the inhibitor code in the Lumic Family Database. He finds it and sends it to Rose’s phone. The Doctor plugs the phone into the computer systems, dropping the inhibitor signal and sending the Cybermen into despair. They explode, setting the factory on fire and our heroes escape in the Zeppelin. The Cyber Controller follows, climbing the ladder, but Pete uses the sonic screwdriver to destroy the ladder and the Controller falls to his death in the exploding factory.

The Doctor plugs the recharged power cell into the TARDIS, and it starts. Rose tells Pete she is his daughter in another universe, but he can’t process the fact. Mickey decides to stay and take care of his elderly grandmother, and to continue to fight the Cybermen with the Preachers.

In this episode, the Cybermen are dialed up to eleven, and we see the despairing, tortured humans inside, which makes them all the scarier. It was well received, particularly the way Mickey finds himself, but Lloyd-Pack’s over-the-top villain was panned. The music is similar to the song “Sheep” by Pink Floyd. We are reminded of the Pink Floyd album cover with a pig like an airship floating over the Battersea Power Station.

The Doctor now says Mickey the Idiot affectionately. There is a hint of the movie Casablanca in which Rick says farewell to Ilsa, when Mickey, now calling himself Rickey, says farewell to Rose and speaks of liberating Paris. When the Doctor discovers how to kill the Cybermen, he wonders if he has the right, just as the Fourth Doctor Tom Baker wondered about destroying the Daleks. The heroes attack the factory from “above, between, and below” in a line from a Gallifreyan nursery rhyme about the Tomb of Rassilon, as seen in the Five Doctors episode.