On a parallel Earth, a deadly new version of the Doctor's old enemy is about to be reborn.
The TARDIS encounters a massive anomaly which causes it to suddenly lose power. The Doctor (David Tennant)
discovers that the time vortex has vanished and his TARDIS is dead. Things begin to look up when Mickey (Noel Clarke) discovers
that they've arrived in London, but it's not the London they know... there are zeppelins in the sky and Rose (Billie Piper)
is startled to discover a billboard advert with photos of her late father, Pete Tyler (Shaun Dingwall). The TARDIS crew has
entered another universe and the ship cannot draw power from this reality's time vortex. However, it turns out there is one
component of the TARDIS that still has power... but it will have to be nurtured, and will take a day or so.
is a major power in this alternate version of London, run by a man called John Lumic (Roger Lloyd Pack), who is confined to
a wheelchair but still exhibits hostile tendencies toward his workers while attempting to complete a top-secret project. One
of the people involved in his project is Pete Tyler, who has been invited to a meeting to discuss a new project, a meeting
also to be attended by the President of Britain (Don Warrington). At his home, Pete's wife, Jackie (Camille Coduri) stops
functioning normally when a signal is received by an earpiece set she wears, from Cybus Industries... an earpiece worn by
most of the inhabitants of London.
The Doctor warns Rose and Mickey not to interfere with this world; it's not theirs,
and the people here are not the ones they know. Mickey goes to see his grandmother, whose death in his reality he feels some
guilt over, blaming himself for a fatal fall she took, but he's kidnapped by the occupants of a van. Inside the van is Jake
Simmonds (Andrew Hayden-Smith), a member of an underground resistance group against Cybus Industries called the Preachers
who witnessed the rounding-up of large numbers of homeless people by one of Lumic's henchmen, Mr Crane (Colin Spaull). He
and his associate Mrs Moore (Helen Griffin) believe Mickey to believe his alternate-universe counterpart, Ricky. However,
later when they arrive at their headquarters, Ricky is present, and Mickey has some explaining to do.
Rose and the
Doctor discover that Cybus is putting out a strange signal, which has affected everyone wearing the earpods. They make way
for a party being held at the Tyler estate, where they become part of the servant staff in order to gain access. Rose realizes
the people she believes she knows as her parents aren't really a part of her life, and that in this universe, "Rose" is the
name of their dog.
Lumic has Crane move to the next phase of their secret project, while the Doctor discovers the
terrible truth about what Lumic is trying to accomplish. At the party, the Doctor and Rose watch as hundreds of metal men
approach the house with orders to destroy all resistance. They are Cybermen, and the rise of their order is happening all
over again in this universe. As the President dies and Jackie flees, the Doctor, Rose and Pete, united with Jake, Mickey and
Ricky, confront the Cybermen, who instead of taking them as hostages, prepare to delete them...