Hide was the ninth episode of the seventh series of Doctor Who, produced by BBC Wales.
It saw the Doctor continue his investigation into Clara Oswald’s true nature, and led her to directly communicate with the Doctor’s TARDIS for the first time, leading into the subsequent episode.
“Caliburn House. Night four. November 25th, 1974. 11:04 pm.”
Professor Alec Palmer and his assistant Emma Grayling are attempting to contact an apparition haunting Caliburn House. Emma is a psychic, and uses her gifts to gain the attention of the “ghost”. They are interrupted by knocking at the front door, and open it to find the Eleventh Doctor and Clara. The Doctor tells Alec that he is looking for a ghost and Clara claims that they are “Ghostbusters”.
The Doctor claims to be from “the Ministry”, and knows who Alec and Emma are. Photographs taken by the professor show the same figure in the same pose throughout the history of Caliburn House. The Doctor and Clara search the house, as a strange creature stalks them through it. Loud knocking is heard, which is said to be associated with the “Witch of the Well”.
The Doctor returns with Clara to the TARDIS and takes a series of photographs of the “ghost” throughout Earth’s timeline. Upset at seeing Earth become a lifeless rock, Clara believes that she is nothing more than a ghost to the Doctor, because as a time traveller he has been to a time when she is long dead. He tells her that she is “the only mystery worth solving”. The Doctor uses his photographs to explain that the “ghost” is in fact a time traveler called Hila Tacorien, who is trapped in a pocket universe in the process of collapsing and being chased by an unknown creature.
The Doctor uses a crystal from Metebelis III to enhance Emma’s thoughts and use them to create a portal to the pocket universe, a reality “well”. He goes to rescue Hila, who escapes, but is trapped in the pocket universe with the monster after Emma collapses. As the professor encourages Emma to try again – finally admitting he loves her – Clara returns to the TARDIS, and after a brief argument with the voice interface (which appears as herself, much to her annoyance), manages to break into the pocket universe and rescue the Doctor from the creature.
The next morning in conversation with Emma, the Doctor reveals that he brought Clara to Caliburn House in order to see Emma, not the ghost. He asks what she senses about Clara, but Emma reports nothing unusual about her. As the Doctor and Clara are preparing to leave, the Doctor inadvertently reveals that Hila is Emma and Alec’s future descendant. Alec and Emma are in love, and the Doctor advises them to “hold hands, and don’t let go”. Then the Doctor realises that the creature in the pocket universe has been trying to return to another creature in the house. He then states that every lonely monster needs a companion, and explains to Clara that the two creatures have been separated through time and space and certain events, and are yearning to be with one another. He describes this as not a “ghost story” but a “love story”. He then returns to the pocket universe, where he reconciles with the monster to bring it back in the exact same manner as before.