Doctor Who S9E7 - "The Zygon Invasion" Recap

Osgood and the Zygon duplicate of her explain to viewers about the peace treaty signed between the human race and the Zygons. These events took place during the Day of the Doctor. They have become linked as a result and refer to each other as sisters. Through Operation Double, UNIT implemented a plan to relocate all Zygons into the human population by having them take the place of the duplicates of Britain. The 'sisters' have the "Osgood Box" which will e used if the ceasefire breaks; this is known as the Nightmare Scenario.

One Osgood is in a desert town and running away from the Zygons. She texts the Doctor with the message "Nightmare Scenario" before being zapped and taken captive by a Zygon. After receiving the message, the Doctor calls Clara but only gets her voicemail. In present day Britain, the Doctor tracks down the two commander Zygons at a school playground as they have taken on the form of two primary school girls. He pleads with them to not break the ceasefire but negotiations stall when another Zygon arrives, throws a smoke bomb and captures the two commanders.

Clara returns to her apartment and finds that she has 127 missed cals from the Doctor. She is going to call him back but then sees a boy on the stairs who is looking for his parents. She helps the boy get back to his apartment and the father takes him away kicking and screaming. Both the father and mother are exhibiting strange behaviour.

Clara meets up with the Doctor and together they go to UNIT where they learn that when one Osgood died, the other was overcome by grief. The ceasefire had started to break down. They receive a video message from the Zygons who are shown to force the primary school girl-Zygons to resume their normal form before they are destroyed.

The Doctor decides to go to Turmezistan to find the missing Osgood and keep UNIT from bombing and destroying it. Clara will keep looking after the ongoings in England, while Kate will head off to New Mexico to visit their stateside base. Unfortunately, the military members that are tasked with taking down the alien hostiles are overcome when the Zygons take on the appearance of the military members' loved ones. The Doctor is able to find Osgood trapped in a basement and frees her. Osgood warns that the Zygons are headed back to England.

Kate is being lead around a ghost town in New Mexico by a sheriff and observing the remains of dead Zygons in dumpsters that have been reduced to stacks of hair-balls.

Clara discovers a hive of Zygon duplicates that have been grown... except that's not how Zygons work. They kidnap the originals, so the Clara we've been watching for most of the episode is her Zygon duplicate. When Clara went to help the young boy, she was zapped and her duplicate took her place.

The Doctor and Osgood are questioning a Zygon and begin to piece together everything that has been happening. Meanwhile, Kate realises that the sheriff she has been led around with is actually a Zygon and is attacked and swapped out for a duplicate. Duplicate-Clara calls the Doctor and informs him that Clara and Kate are dead, before shooting a bazooka at the plane he is flying in on.

Doctor Who airs on Saturdays on BBC One.