The Doctor (Matt Smith) and his companions, Amy (Karen Gillan) and Rory (Arthur Darvill) find themselves switching back and forth between two realities. In the first, Amy and Rory stopped travelling in the TARDIS five years ago and are happily married in Leadworth and expecting a child. They are chased by Eknodine aliens disguised as elderly townsfolk. Then, they are trapped in a powerless TARDIS, drifting toward a freezing cold star. An apparition called the Dream Lord (Toby Jones) is responsible. They can awaken by killing themselves, if this is a dream, but if it is not a dream they will die.

The Dream Lord keeps Amy awake while the Doctor and Rory fall asleep and return to Leadworth. Amy has to choose between a peaceful life with Rory or an exciting life with the Doctor. She returns to Leadworth, but an Eknodine kills Rory. She realizes that is the unreal life and they all wake up in the TARDIS, but the Doctor directs the TARDIS to self-destruct.

They wake up alive and the Doctor says that both realities must have been false because the Dream Lord has no power over the real world. It all came from a hallucinogenic pollen that got into the TARDIS. Rory realizes that Amy, in the dream, killed herself for him, and she really loves him.

The episode was partly inspired by Total Recall. Actually, the whole episode took place in the TARDIS. The Dream Lord was a manifestation of the Doctor’s self-hatred. Some reviewers liked the surreal aspects of the story and the dark humour, but others were not impressed.