In the prequel, a hooded messenger tells the Doctor that a woman, Darla von Karlsen, wants him to save her daughter. He is given the space-time coordinates of the planet Skaro.
The Doctor (Matt Smith) is kidnapped by the Daleks and taken to the Parliament of the Daleks. Kidnapped with him are Amy (Karen Gillan) and Rory (Arthur Dargill), who have now split up. The Daleks ask the Doctor for help. The starliner Alaska has crashed into a planet inhabited by insane, battle-scarred Daleks—the Asylum—and it ruptured the planet’s force field. Even the Daleks are afraid of these Daleks, who are stark raving mad. Personally, I wonder how they can tell.
The Doctor, Amy, and Rory are supposed to deactivate the remaining force-field so the Daleks can destroy the planet. The Doctor figures they will happily destroy him too and plots an escape with a teleporter to the Dalek ship. A survivor of the Alaska crash, Oswin (Jenna-Louise Coleman) agrees to deactivate the force-field if the Doctor will rescue her. Amy and Rory reconcile.
The Doctor manages to get to Oswin through the insane Daleks and she saves him by removing the Daleks’ memories of him from their telepathically shared knowledge. The Doctor discovers with horror that Oswin is a Dalek. They converted her to preserve her genius-level intellect. Her mind has retreated into a fantasy of being human. She does indeed deactivate the force-field and asks the Doctor to remember her as human. The Doctor, Amy, and Rory teleport back to the TARDIS and the planet is destroyed. The Daleks fail to recognize the Doctor.
Twenty-five different kinds of Daleks, from throughout the series, appear. Many of them were loaned to the BBC by private owners after a call went out for Daleks of different eras. The episode received positive reviews, but many reviewers wondered why the Ponds broke up in the first place. The story was nominated for the 2013 Hugo. There is a new title sequence. Amy Pond is a model, and Karen Gillan is photographed with curly hair like River Song. Producer Steven Moffat thought the Daleks had become too cuddly and child friendly as British TV icons and wanted to make them scary again. Karen Gillan admitted that she had not been the slightest bit scared of Daleks until this episode. Jenna-Louise Coleman would become a companion later. Her scenes were filmed over six days on a closed set to keep her appearance a secret. Just how she could turn up later as a young woman despite actually being a Dalek, and dead to boot, will be a hard one to explain.