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The Zygon Invasion was the seventh episode of series 9 of Doctor Who. It served as a sequel to 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 Missy's Cyberman invasion, Osgood and her Zygon duplicate had become 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.


A long time ago, the Doctor made a deal in the Tower of London. 20 million Zygons 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?


The episode opens with "Once upon a time... There were three Doctors..." It then 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 is 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, the town Truth or Consequences is under attack. Osgood is fleeing in all the chaos, as the residents fight back against the attackers. Taking shelter in a police department, Osgood pulls up the Doctor's number on her phone to call him. However, hearing someone enter, Osgood hides under a desk and sends a text to him instead. Just when she thinks she is 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.

Later, the Doctor is sitting on a swing in a park, trying to call Clara; not wanting to draw attention, he codenames himself "Doctor Disco". The Doctor leaves a message saying that he is keeping an eye on two dangerous creatures, which are two little girls playing on a slide. The Doctor attempts talking to them; it is revealed that they are the Zygon high command, Jemima and Claudette. However, the Doctor receives a call from Kate Stewart; he attempts to make her see that it is 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 into 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.

Drakeman Junior School

UNIT arrives at the Zygon nest

The Doctor, Clara, Kate and Jac head to the location of the Zygon nest. It is 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 is 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 is also where Osgood went missing after a Zygon outbreak. Kate also reveals that UNIT has found what appears 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 aeroplane, 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 its 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 is 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. The Zygons exit their base disguised as various loved ones of the troops. The soldiers are torn, but ready to kill. Despite the order to fire, the soldiers are persuaded to come inside. The Doctor shouts no in disbelief; UNIT soldiers are still THIS stupid? He and the head of the operation run inside, finding the soldiers reduced to piles of wire. 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 has 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.

Kate Stewart

Kate defends herself.

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 the citizens are 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 is 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 are 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 to early in his Seventh). The Doctor smiles, telling her that he did not stop wearing them; "I've got question mark underpants." Osgood jokes that it makes one wonder what the question is.

Osgood confuses Twelve

Osgood states she is only "Osgood", refusing to answer whether she was the original or the Zygon double

The Doctor tells Osgood that he will keep her secret; she is 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 is wrong; he is 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 have 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 is 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 goodbye to the Doctor.


Uncredited cast[]


General production staff

Script department

Camera and lighting department

Art department

Costume department

Make-up and prosthetics



General post-production staff

Special and visual effects


Not every person who worked on this adventure was credited. The absence of a credit for a position doesn't necessarily mean the job wasn't required. The information above is based solely on observations of the actual end credits of the episodes as broadcast, and does not relay information from IMDB or other sources.



  • Drakeman Junior School is located in Dulwich.



  • Daniel Powell was the "approving officer" on one of the Truth or Consequences closed case files.
  • The file pertains to Callum Darbyshire (born 1993), living under the address 10 Fictional Close, NM.
  • It also details a witness: Daniel Thornes (born 12/21/1993), living under the address 72 Made Up Crescent, NM.
  • According to the statement, Derbyshire was placed under arrest after exhibiting "loud [..] behaviour under the influence of alcohol, towards other members of the public". Powell and his partner confronted Darbyshire. The offender attempted to assault a police officer, but was subdued and attained. The officers "gave him his rights and took him into custody".

The Doctor[]





Story notes[]

  • The episode had the working title of Invasion of the Zygons.
  • The Radio Times programme listing was accompanied by a small colour shot of Osgood and the Doctor, with the accompanying caption "Doctor Who / 8.15 p.m. Osgood is snatched by aliens, prompting a round-the-world rescue mission".
  • The "Clara" in most of this episode is a Zygon duplicate, making this, in a limited sense, the second consecutive episode in which Clara has only a brief appearance.
  • Peter Capaldi and Rebecca Front previously worked together on The Thick of It.
  • The strong subtext in the story concerning contemporary immigration and terrorism has been noted by many commentators and reviewers and has been widely discussed on social media.
  • Steven Moffat chose Peter Harness to write the script having been impressed with the emotional discourse between the Doctor and Clara in Kill the Moon.
  • Although he enjoyed the opportunity to tackle such sophisticated ideas and introduce an unusually gritty tone, Peter Harness was also mindful of the need to appeal to the younger members of the audience. As such, he decided that several of the key Zygons would be masquerading as children, with their base of operations located at a school.
  • One of the leaders of the Zygon splinter cell was called originally Blinovitch, and had taken the form of Courtney Woods; in early drafts of Kill the Moon, Blinovitch was revealed to be the surname Courtney would use as an adult. In the late stages, Blinovitch was the captive Zygon taken aboard the presidential aeroplane. At one point, she escaped her bonds and attacked the Doctor, only to be stopped by Osgood, who revealed herself to be a Zygon as well. This would have confirmed that the Osgood murdered by Missy in Death in Heaven was the human original.
  • In the original script, much of the action took place in Azerbaijan, as opposed to the fictional Turmezistan. Osgood had been taken there after her capture by the radicalised Zygons in a raid on a UNIT safe house in London.
  • Briagdier Winifred Bambera was originally meant to return, now promoted to General. Her role was given to Colonel Walsh.
  • A deleted scene saw Colonel Walsh ruthlessly gun down a Zygon who resembled her son.
  • Originally, McGillop and Corporal Carol Bell were amongst Kate's staff in London. Both their roles went to Jac.
  • The radicalised Zygons originally used London Underground trains to ferry their human captives, rather than lifts.
  • The failed UNIT attack on the Zygon hatchery originally left the real Clara hospitalised and on the brink of death after being shot.
  • This two-parter formed Block Four of season nine.
  • Daniel Nettheim had been a fan of the during his childhood in Australia, and who had previously directed several episodes of K·9 in his home country.
  • The Zygons originally made use of foot-long caterpillar-like creatures.
  • Claudette and Jemima were originally supposed to be twins, until it was decided that having sisters play the role would convey a suitable sense of association.
  • In the script, the safe in the UNIT safehouse was hidden behind a portrait of Sergeant Tom Osgood, who was implied to be the father of the modern character.
  • Peter Harness requested that one Osgood wears a variation on the Seventh Doctor's question-mark pullover. However, the other Osgood paired the Fourth Doctor's scarf with a bow tie of the type worn by the Eleventh Doctor, as opposed to Harness' suggested attire of the Fifth Doctor's vest with a sprig of celery.
  • During the sequence of the Doctor bolting for the TARDIS after their abduction, Peter Capaldi injured his knee. Since the tear to his meniscus would require surgery and recuperation time, it was agreed that filming for both the story and the season would proceed as scheduled, with the production team making any necessary accommodations to ensure that he did not sustain further injury.
  • Shots of Bonnie atop the White Cliffs of Dover were captured at Nell's Point, which had previously been the site of the holiday camp in Delta and the Bannermen had been filmed; its demolition had been completed in 2005.
  • Lydstep Flats in Cardiff portrayed Clara's flat, as it had done in The Time of the Doctor. It had previously portrayed the Powell Estate.
  • The UNIT massacre originally took place in a hangar.
  • A deleted scene saw Clara receiving a voicemail (heard by Bonnie, and Jac) revealing that her father has been replaced by a Zygon (and, therefore, possibly killed).
  • Originally, the Doctor would've forgot about the previous Zygon encounter, and when told it involved multiple versions of him, he'd bring up the Black Hole with Omega, the Death Zone with the Raston Warrior Robot and Big Ron, before realising what they were talking about.
  • This two-parter is the first televised appearance of the Zygons without Tom Baker.


Filming location[]

  • Allensbank Primary School, Cardiff
  • Canal Park in Cardiff
  • Cathays Cemetery, Cardiff
  • The Old Custom House
  • Lydstep Flats in Cardiff
  • Barry Shooting Range in Barry
  • eCubed Solutions at MOD St Athan
  • Fuerteventura ("New Mexico" scenes)
  • Sennybridge Training Area in Sennybridge
  • St Catherine's Church in Cardiff
  • MOD Caerwent
  • Nell's Point

Production errors[]

If you'd like to talk about narrative problems with this story — like plot holes and things that seem to contradict other stories — please go to this episode's discontinuity discussion.
  • Immediately after the opening credits, as the camera pans across a park, a crew member holding a microphone can briefly be seen reflected in the TARDIS's "Police Box" sign.
  • Right after she gives the Doctor a mock salute as he boards the presidential plane, Jenna Coleman can be seen sneezing, but the scene continues without interruption.


Eighth Doctor question mark boxers

The question mark boxers appear briefly. (COMIC: The Glorious Dead)

Home video releases[]

DVD & Blu-ray releases[]

  • The Zygon Invasion was released as part of the Series 9, Part Two DVD and Blu-ray boxsets in region 1/A on 26 January 2016, in region 2/B on 4 January 2016 and in region 4/B on 13 January 2016,
  • It was later released as part of the Complete Ninth Series DVD and Blu-ray boxsets in region 1/A on 5 April 2016, in region 2/B on 7 March 2016 and in region 4/B on 9 March 2016.

Digital releases[]

  • In the United Kingdom, this story is available on BBC iPlayer.

External links[]


  1. Coleman actually plays Bonnie, who impersonates Clara, in the majority of her scenes.
  2. Oliver plays both the human and the Zygon members of Operation Double. Both are seen together in the recorded video messages.
  3. Think I was just left off the credits of Doctor Who just now. I did the Zygon voices. If I'm mistaken, apologies. Credits move so fast ;-) - Nicholas Briggs on Twitter
  4. Credited on the DVD and Blu-ray version, as well as in DWMSE 42, but not on broadcast.
  5. Ratings DW