An accident in a factory on the Earth in the future causes a doppleganger to be destroyed in a vat of chemicals.
The Tardis is hit by a solar tsunami which is probably a posh way of saying solar flare and forced to land in the grounds of a fort. The Fort is a factory whose employees are a mix of humans and doppelgangers (Gangers). The Gangers are a wax like recreations of the humans and who do all the work. The Gangers are created in large baths of wax in much the same way as the Cylons are in the re-imagined Battlestar Galactica.
The Doctor tries to persuade the humans to leave but the humans refuse. The solar flare hits the planet and everyone is knocked out cold which The Doctor believes for five minutes but turns out for more than an hour.
The Doctor attempts to bring the two groups together. It seems to be working and the two groups join together. However, Mirandal, one of the humans throws the Doctor's attempts away and starts a war between the groups.
Rory befriends one of the inhabitents of the fort called Jenny Lucas who believes that she is human. However Jenny turns out to be a Ganger but that doesn't change Rory Williams view of Jenny. Amy Pond stays with the Doctor throughout the episode.
The Gangers manage to steal the chemical suits so hurt the humans. At the end of the episode, the Doctor's Gangers makes an appearance.
Continued in The Almost People.