Following the flashback, we see a video of Osgood and Osgood, which one can safely surmise was shot prior to her unfortunate demise at the hands of Missy. In it, she, and her Zygon counterpart explain the ramifications of the peace treaty breaking down; the so-called "Nightmare Scenario". She also makes mention of “The Osgood Box”, which she hopes we will never have to use, so it’s a fairly safe bet that it will come into play in the next episode!
We then cut to Osgood, who, in a deliberately ambiguous scene, is seen standing at a grave, simply marked "my Sister”. To me, this heavily implies that her Zygon counterpart is dead, however, as the story progresses, it transpires that things may not necessarily be so clear cut.
I must confess, I'm not entirely comfortable with Osgood's explanation that Zygons are a predominately peaceful race, who happily assimilate into other cultures. This is clearly intended as a reference to Muslims and Islam, and to the current geo-political climate, however it is well established that Zygons are, or were, anything but peaceful.
Cut to the present day, and Osgood is running for her life, into a police station, with a Zygon in hot pursuit. Whilst hiding under a desk she uses her inhaler further implying that she is human,and that it is her Zygon duplicate occupying a hole in the ground. She manages to fire off a text message to the Doctor, who, aboard the Tardis, is hammering out a rather splendid rendition of Amazing Grace on his electric guitar. Opinion seems fairly divided on the guitar; personally, I rather like it, IF used appropriately. It evokes memories of the recorder playing Second Doctor. The long, protracted guitar sequence of The Magician’s Apprentice didn't quite work, but whilst aboard his own ship, why shouldn't he pluck out a tune or two!
Landing in Brockwell Park, London, the Doctor is attempting to call Clara (127 times!). He makes contact with two Zygons who have taken the form of two small girls. They are the Zygon High Command, and rogue Zygons waste little time in abducting them.
At a UNIT safe house, we see the welcome return of Kate Lethbridge-Stewart and Jac. Drawing clear parallels to ISIS, a faction of Zygons have formed a rogue splinter cell, and are holding Osgood hostage. They even send UNIT an ISIS style video, complete with snazzy logo, in which Osgood reads their demands. “There will be truth, or there will be consequences…”
Heading to the Zygon High Command Centre, which is set, somewhat curiously, in a junior school, Kate explains that 20 million Zygons have been permitted to take the form of the nearest available human beings. Again, I’m not entirely comfortable with this concept, and neither, I would imagine, are the 20 million humans, who now have aliens masquerading as them. Yet we are given to believe that the human race has cheerfully embraced this. Given the political nature of the story, it is surprising that no one has, as yet, given any thought to the security implications of this.
It is here we learn that, since the ceasefire, there have always been two Osgood's. The Doctor expands upon this by stating that they are both human and Zygon, maintaining a live link. Kate elaborates that after Osgood is killed, “other Osgood” goes mad with grief, and heads off to the United States to go undercover.
The Zygons send UNIT a second hostage video, demanding the right to live as themselves, and summarily execute the Zygon High Commanders. UNIT establish that they are holed up in a settlement in Turzmenistan, which Kate immediately proposes bombing; she’s certainly her father’s daughter! Clara “realises” that ‘Truth or Consequences’ is the name of a town in New Mexico, which is the last place a signal was received from Osgood. Her knowledge of the name of the town becomes much clearer later in the episode, and, for those who are aware that ‘Truth or Consequences’ is a real town, her “trivial pursuit” explanation seems perfectly plausible.
In a particularly nice scene, Clara asks Lethbridge-Stewart about weapons. Her response is that "there was an attempted Zygon invasion before in the 70's or 80's. One of our staff was a Naval surgeon, worked at Porton Down on captured Zygons, developed Z67".
In his last on screen mention, in the 1985 story Mawdryn Undead, The Brigadier mentioned to the Doctor that Harry Sullivan had been seconded to NATO and was working on "something hush-hush at Porton Down".
The Doctor tasks Clara and Jac with ensuring the safety of the U.K.; it is, after all, “their country”, a theme Peter Harness had previously explored, albeit on a planetary level, in Kill The Moon. Kate is to make her way to ‘Truth or Consequences’ and The Doctor takes the Presidential Aircraft to Turzmenistan, to attempt to negotiate peace. This seems somewhat contrived, given he could have easily travelled by Tardis. Similarly, he could have deposited Kate in ‘Truth or Consequences’, before heading to his negotiations.
There are some delightfully pleasing throwbacks to Doctors past, with a portrait of the First Doctor gracing the wall at UNIT headquarters. It seems a curious choice, given it was predominately the Third Doctor who was most associated with UNIT, however the Brigadier had encountered the First, on two occasions, so it's presence, while fleeting, is not too jarring. The most obvious nod to the past is, of course, Osgood's "question mark" jumper, a hallmark of the Seventh Doctor.
During his meeting with the two Zygon Commanders, the Doctor refers to the Zygons as "blobby factions", a description used by Ace in Remembrance of the Daleks to describe the two warring Dalek factions. In another, less obvious nod to Remembrance, there is a sign in a window in Truth or Consequences, which states "No Dogs, No British", not dissimilar to the racially charged sign at the B&B owned by Mrs Smith.
The Zygons are well used, look and sound menacing, although, for me, there is something a little "off" about their updated design. Of all the classic series alien designs, they are, perhaps, the most timeless, and to this day still look fantastic. The updated versions are a little more robust in design, more muscular and “ribby”. The faces, despite (or perhaps because of) their razor sharp teeth and more human countenance, don't seem quite as sinister. Nevertheless, they are still pretty faithful to the original design, something which is to be lauded. One only has to look at the dreadful mess that was made of the Silurians, who are barely recognisable from their earlier counterparts.
Meeting Colonel Walsh, capably played by Rebecca Front, the Doctor introduces himself. Her response that "we know who you are" has distinct echoes of the Harriet Jones stories. At the Zygon training camp in Turzmenistan, UNIT plan to storm the church where the Zygons are located, with only 30 minute window before an air strike. This was a theme frequently exploited during the Pertwee years, arguably to better effect.
The Zygon ability to take the form of our most loved ones is a chilling prospect, and one which is well realised. In an obvious trap, they present as family members of the UNIT soldiers, tasked with storming the church, and in one of the highlights of the episode, Hitchley is led to believe that his own mother is being held hostage. It would be easy to write this scene off, given that it is patently a trap, however, if confronted by the visage of a loved one, how many people could, with absolute certainty, pull the trigger?
Having rescued Osgood, she and the Doctor head back to the U.K. aboard the plane, where she expands on the human/Zygon relationship. It had been previously established in Terror of the Zygons that replicated humans had to kept alive in order to refresh the body print. Those days are now past; those are the “old rules”, and Osgood explains that while Zygons are able to pluck the memories from human beings, now they need only be kept alive should further information be required, otherwise the original human counterpart can die. There is a nice exchange between Osgood and The Doctor, in which the Doctor speculates that she is human. Osgood states that she is both human and Zygon, giving the Doctor another hybrid to ponder upon. The interaction between Capaldi and Ingrid Oliver feels natural, compelling and the chemistry between the two characters is superb. (She’d make a bloody good companion!)
Meanwhile Clara leads the UNIT troops underground, where it is revealed that many humans are encased in pods, one of which is Clara herself. The revelation that Clara has been substituted with a Zygon works fairly well, although the flashback seemed completely unnecessary. The audience is capable of deducing when it happened, and spoon feeding us is, frankly, a tad insulting to our intelligence. Similarly, Jenna Coleman doesn’t quite manage the Machiavellian facial expression she is attempting to portray. The episode ends on a superb cliff-hanger, with Zygon Clara firing a missile at the aircraft carrying The Doctor and Osgood.
The main weakness of the story is to be found in its greatest strength. The political nature of The Zygon Invasion works well, for the most part, however it lacks any subtlety, and the allusions to The Middle East tend to feel forced rather than nuanced. “I'll happily bomb the hell out of anywhere”, and lines about migrant Zygons “helping themselves to benefits” are much less refined than the script deserved.
The supporting cast is as strong as ever, Kate and Osgood are decent, well crafted, believable characters, and their interaction with the Twelfth Doctor works well. On the downside, The Doctors attempts to appear "cool" don't really work, and names like "Doctor Disco" or "Doctor Funkenstein" really do nothing for his normally brusque, detached character.
Overall, despite its many flaws, I enjoyed this episode. I mean REALLY enjoyed it! It was a superbly entertaining piece of television, and despite some heavy handed, unsubtle scripting, it is hard to believe it flowed from the pen of the same person who spewed out Kill The Moon. The Zygons appearance in Day of the Doctor was something of a wasted opportunity, so it’s a positive joy that they finally have a full length story focused on them.
The Zygon Invasion is a fast paced, thought provoking story, unashamedly subtle as a house-brick to the face, and containing just enough twists and turns to keep you on your toes. Yes, there are plenty who will have seen the twist with Clara a mile away; I wasn’t one of them, which I suspect added to my enjoyment. For me, it’s the strongest episode of the season, so far. Two parters in series nine have been notoriously weaker in their concluding episode, and so I really hope this one bucks that trend, and that the next episode doesn’t let it down. More than anything, it feels like a classic era story; whether it earns a “classic status” remains to be seen. It’s not a perfect story, but it’s certainly deserving of the 9/10 I’m awarding it.