The Zygon Invasion

"The Zygon Invasion" is the seventh episode of the ninth series of the British science fiction television series Doctor Who. It was first broadcast on BBC One on 31 October 2015, and written by Peter Harness and directed by Daniel Nettheim. The episode is the first episode of a two-part story, the second part being "The Zygon Inversion", which aired on 7 November. In the episode, a peace treaty agreed between humans and shapeshifting aliens called Zygons in the 50th anniversary special "The Day of the Doctor" has started to fail. A radicalised splinter group of Zygons, seeking to no longer hide among humans but be themselves, takes over Zygon High Command and seeks to invade present-day Earth and neutralise UNIT. The alien time traveller the Twelfth Doctor (Peter Capaldi) attempts to keep the peace. Plot Ever since the War, Tenth, and Eleventh Doctors ensured the creation of a peace treaty between humans and Zygons, there existed two versions of UNIT scientist Osgood: one human and a Zygon duplicate. 20 million Zygons have been resettled on Earth, peacefully living out their lives disguised as humans. The Doctor leaves the Osgoods the Osgood Box to be used as a last resort. After one of the Osgoods was killed, the other left UNIT and disappeared. In the present, Osgood is captured by a splinter group of Zygons in the town of Truth or Consequences, New Mexico just after sending a warning to the Twelfth Doctor that the treaty is failing. In London, the splinter group, which seeks to be themselves no matter what, kidnaps and kills Zygon High Command, leaving a Zygon called Bonnie in charge. In Turmezistan, Osgood is forced to read a video message declaring the splinter group's intent to go to war. At the block of flats where Clara lives, Clara is knocked unconscious and hidden in a pod underground. Bonnie takes Clara's place.