Something terrifying is hiding in Caliburn House, and the Doctor finds himself part of the ghost hunt.
The Doctor (Matt Smith) and his companion Clara Oswald (Jenna-Louise Coleman) visit a mansion in the 1970s owned by Professor Alec Palmer (Dougray Scott), which appears to be haunted. Palmer’s assistant, Emma Grayling (Jessica Raine), is an empath who is able to connect to the ghost. The Doctor discovers that the ghost is really a time traveller from the future (Kemi-Bo Jacobs) who is trapped in a pocket universe, and travels there to rescue her. There he discovers a bizarre “Crooked Man” (Aiden Cook), who is also looking to be taken out of the pocket universe and reunited with its mate in the mansion, who had been the source of much of the mysterious activity in the mansion.