The Zygon Invasion ( TV story ) It served as a sequel to events set up in the 50th anniversary special " The Day of the Doctor " , having a beginning sequence dedicated to the relative plot point of this story . The episode saw the return of Osgood , curiously after her death in the series 8 finale " Death in Heaven " , with this episode revealing that before ' s Cyberman invasion , Osgood and her Zygon duplicate had gotten so identical to each other that they refused to say which was the Zygon and which was the human , making it unknown which Osgood was actually killed by Missy . It ' s shown that the newer breed of Zygons have enhanced abilities ; they can now read the minds of their enemies and take the form of whatever it is they love to lull them into a false sense of security before killing them . It is effectively the second " companion - lite " story in a row as Clara is revealed to have been kidnapped and replaced with a Zygon duplicate called Bonnie ; the real Clara , as a result , appears in only one scene , though this fact is not revealed until the end of the episode . It also continued the thematic concept of the Doctor apparently facing death , with the end of the episode setting up yet another opportunity for the Doctor to reflect on his mortality . Synopsis . A long time ago , the Doctor made a deal in the Tower of London . 20 million Zygon s walk among us , in human form , living undetected in peace and harmony . But cracks are showing in this delicate peace . Humans and Zygons are disappearing . In city apartment blocks , lifts are going missing , and far below the streets of Britain , alien pods are growing in secret caverns . To top it all off , UNIT ' s scientific advisor , Osgood , sends a desperate message to the Doctor - but since Osgood is long dead , how is that even possible ? Plot . The episode opens with " Once upon a time . . . There were three Doctors . . . " It the shows the War , Tenth and Eleventh Doctors giving grim stares from " The Day of the Doctor " . " Two Osgoods . . . " Osgood is shown cowering as a Zygon takes her form and asks for her inhaler . " And one treaty " The Doctors are shown erasing the memories of both humans and Zygons in the conflict , forcing them to create a peace treaty . On video , two Osgoods appear seated next to each other and box that looks like the Moment . Because Osgood is a fan of the Doctor , one is wearing a bowtie and scarf ; the other is wearing a question mark jumper . They explain Operation Double - the peace treaty with the Zygons . 20 million Zygons have been given asylum on Earth so long as they maintain human forms . Zygons , just like humans , have the capacity for both great evil and great good . The box is the Osgood Box , which can start and end a war with humans and Zygons . If a Zygon is killed , regardless of the circumstances , it will spark a rebellion . Fast - forward to right after Missy ' s failed attempt to turn humanity , living and dead , into an army of Cybermen . Osgood in a graveyard , crying for the loss of her twin . She leaves flowers for the other Osgood on a grave that simply reads " My Sister " . 2015 , New Mexico , Osgood flees from an attack in the town Truth or Consequences . Taking shelter in a police department , Osgood tries calling the Doctor . However , hearing someone enter , Osgood hides under a desk and sends a text to him instead . Just when she thinks she ' s safe , a Zygon grabs her . Inside the TARDIS , the Twelfth Doctor is rocking out to " Amazing Grace " on his electric guitar . Hearing the console beeping , he stops playing and rushes over to the monitor to see an incoming message from Osgood : " Nightmare Scenario . " The Doctor looks on grimly , realising that a break in the ceasefire has finally come . The Doctor is next seen sitting on a swing in a park , trying to call Clara ; not wanting to draw attention , he code names himself " Doctor Disco " in his messages . Noticing two little girls , the Doctor attempts talking to them ; it ' s revealed that they ' re the Zygon high command , Jemima and Claudette . However , the Doctor receives a call from Kate Stewart ; he attempts to make her see that it ' s only a splinter group of Zygons wanting war , not the entirety of the race . Unfortunately , at that moment , the leaders are captured by the splinter group , Truth or Consequences . Left with nothing to do , the Doctor decides to go in to UNIT for more resources . Meanwhile , Clara arrives home from work and checks her phone , to discover that the Doctor has left over 127 messages on her phone . She starts to listen to her voicemail , but finds a child crying on the stairs of her apartment complex . Learning that he cannot find his parents , Clara follows Sandeep back to his apartment , finding it empty ; however , the moment she turns around , the child ' s parents appear , saying nothing is wrong despite the boy ' s screams . Clara is concerned by this , but is next seen leaving without much of a care ; she calls the Doctor , asking if he seriously called himself " Doctor Disco ? " In the meantime , the Doctor learns about the current situation : the splinter group is holding Osgood hostage in order to get information on the Osgood Box . Kate also explains that there have always been two Osgoods , the human and the Zygon , ever since the ceasefire , while the Doctor says that " both of them " were real ; the duo refused to single each other out as human and Zygon , seeing each other as equals . Clara joins them . The Doctor , Clara , Kate and Jac head to the location of the Zygon nest . It ' s hidden under Drakeman Junior School . The Zygon ' s high command took the form of two girls posted on the notice board . Kate explains that the new - born Zygons took the form of whatever UK citizen was closest to them ; afterwards , they were dispersed around the world to blend in and live their lives as humans . Inside a basement room , the Doctor finds the control node responsible for communicating with the Zygons and birthing more of them . As the Doctor works the controls , Clara asks if he wants to " be alone " with it . He explains it ' s how the Zygon technology works . He pulls up the thoughts of the Zygons around the world , which is of great paranoia . They receive a new message , which shows the High Command being executed by the rebels , who declare themselves the new leaders . The group identifies themselves as Truth or Consequences . However , Clara states she heard it was a town in New Mexico , on " Trivial Pursuit " ; it ' s also where Osgood went missing after a Zygon outbreak . Kate also reveals that UNIT has found what appear to be a Zygon training post in Turmezistan , which may serve as T . o . C . ' s base . The Doctor tells Kate to investigate New Mexico , to find out what caused the Zygons to attack ; he tells Clara and Jac to remain in the UK , while he heads to Turmezistan . He asks Kate if UNIT still has the presidential airplane , prompting Clara to remind him that he hates being president of Earth . The Doctor states he likes poncing around in a big plane . At an airport , the Doctor boards Boat One giving a double peace sign to Clara and Kate . Clara wonders if they have any effective weapons against Zygons . Kate tells her of Z - 67 , created by a UNIT naval officer back in the 70s or 80s , which basically turns Zygons inside - out . When Clara asks about it ' s location , Kate tells her it was taken by " someone with a TARDIS . " Kate leaves for America . Clara asks Jac if they can stop by her flat before they do anything ; it ' s not a problem . Once Clara collects what she needs , she and Jac spot a body being moved into a lift . However , once they check it on the ground floor , there is no - one in it . They board the lift , finding red ooze coming from the button panel . They pull it back to find that the Zygons have modified the lift ; activating the device , the lift goes to a subterranean area full of pods . Jac states that they need to bring in reinforcements . In Turmezistan , the Doctor arrives at a command post , giving a flamboyant introduction for himself , only to be told that they know who he is . He learns that they are about to bomb the village ; however , the controller of the remote controlled bomber sees Zygons that have taken the form of her husband and child . The Doctor realises that the Zygons ' powers have grown ; they can now read minds and take the form of whatever their targets love most . Despite the predictable military ' s suggestion for aggression , the Doctor suggests looking for Osgood before trying to bomb the town . Arriving in the Zygon - occupied village , the Doctor informs his UNIT troops to avoid killing as much as possible as they are going to need someone to negotiate with . Unfortunately , the troops are tricked by the Zygons , who take the form of their loved ones , and vaporised . Given only ten minutes before UNIT begins bombing the Truth or Consequences splinter group , the Doctor searches the now empty Zygon base , finding Osgood tied up in the cellar ; they barely manage to escape as the bombing begins early . A Zygon returns to kill them and gets knocked out by the debris , allowing easy capture . Back in the UK , UNIT arrives to exterminate the Zygons pods . Clara takes a gun , oddly elated at the idea of violence . Jac is suspicious of the pods , but Clara says that they need to destroy them or face whatever the Zygons are creating with them . She pulls gunk off a pod , revealing a copy of her inside the pod . Clara is shocked she ' s been cloned . However , Jac points out that Zygons do not clone humans , they replace them ; she then comes to the horrifying conclusion that Clara is a Zygon and orders her troops to flee . However , Zygons cut them off , blocking off every available way out . Jac begs for the Zygons to let them live , but fake Clara orders their murders . The UNIT personnel scream in horror . Flashback . Right after Clara sees Sandeep being carried away , a Zygon zaps her head and knocks her out . It takes her form , saying her name is Bonnie . The Zygons needed someone close to the Doctor to impersonate so they could remove him to ease their takeover . At the same time , Kate is investigating what caused the Zygons to attack Truth or Consequences . Finding an officer with the badge C . Norlander , Kate is shown all that remains of the rest of citizens is piles of sparking wires . Kate refuses to answer whether or not she brought back - up . Inside the police station , Norlander explains that " one of the Brits " turned into a reptile one day ; then the rest attacked the residents . Kate wonders how it happened . Norlander states that a young Zygon had trouble maintaining its body print . Kate becomes wide - eyed ; she ' s talking to a member of the splinter group . The Zygon reverts back to its true shape to kill her ; Kate readies her gun . Moments , later " Kate " confirms UNIT in North America has been neutralised to Bonnie . Bonnie states that UNIT is almost neutralized on her part ; there ' s just two threats left . . . Meanwhile , the Doctor and Osgood chat on the plane , which is heading back to the United Kingdom . He compliments her on the question mark motif ; she notes that he used to wear them ( between late in his Fourth incarnation and early in his Seventh ) . The Doctor smiles , telling her that he didn ' t stop wearing them ; " I ' ve got question mark underpants . " Osgood jokes that it makes one wonder what the question is . The Doctor tells Osgood that he ' ll keep her secret ; she ' s the original . If she was the Zygon Osgood , she would have changed back in days after Missy killed her " sister " . However , Osgood tells the Doctor that he ' s wrong ; he ' s thinking about the rules of infiltration . She explains Zygons only need the original alive if they wish to mimic their personality ; their form , however , can be kept indefinitely . ( However , should they chose to revert back to Zygon form , they will not be able to change back into that form , as the original is not around . ) Startled by this news , the Doctor asks whether Osgood is the Zygon or the human ; however , Osgood starts that she is herself and no - one else . Their captive comes around , and the Doctor begins to try interrogation . The Zygon recognises the Doctor as president of the world , stating that splinter group wants the world . However , the Doctor is quick to point out that the Zygons are outnumbered by the humans . It laughs at the Doctor , stating that they ' ve had months to infiltrate all the countries of the world ; Truth or Consequences has won the first battle , but now it is time to initiate the war to claim the planet from humanity . At that time , Bonnie is watching the plane fly by ; she puts together a rocket launcher , and takes aim . The Doctor calls Clara , only to get Bonnie , learning that he ' s talking to the leader of the splinter group Truth or Consequences . However , the Doctor immediately realises the danger , warning Osgood . Bonnie launches the rocket , saying good - bye to the Doctor . Home video releases . DVD releases . " to be added " Blu - ray releases . " to be added "