How would you react if you found out your reality wasn’t real? That was the question posed by Steven Moffat during Extremis last night. It’s a deep question and one that doesn’t exactly have an easy answer. While it is not exactly a new concept to Sci-Fi, a very successful movie trilogy has already dealt with humans discovering they’re trapped in a simulation of the real world for instance, Extremis dealt more with the psychological aspects of such a revelation. For how would you react if you discovered you weren’t actually “you” and were just a simulation of the real “you”? Bits of code programmed to think and feel like the real “you”? That every thought you have isn’t yours and is just a programmed response? It’s an incredibly terrifying question and, as we saw with Bill, it’s an idea most of us will refuse to accept. It also becomes incredibly terrifying when we consider the fact that even though we can’t prove we’re all in a simulation, we can’t exactly prove we aren’t either…

For this is where Extremis excelled; posing a deeply philosophical question and surrounding it in a thrilling Da-Vinci Code-esque story with a forbidden book hidden deep in the Vatican’s forbidden library complete with alien Monks roaming the halls. Doctor Who does The Matrix meets The Da-Vinci Code is probably the most apt description of the episode. And it still wouldn’t come close to describing how damn good the whole thing is.

While Doctor Who has done the whole “what you think is real isn’t real” before in the fan-favourite episodes Amy’s Choice and Last Christmas, Extremis took the concept to a whole new level (amusingly it seems to now be tradition for each companion to be trapped in a fake world for at least one episode). The psychological ramifications of discovering your life is nothing more than computer code is terrifying and the scenes where the characters discover this were chilling. Calling to mind that all time bone chilling moment back in Forest of the Dead where Miss Evangelista revealed to Donna Noble that she was in a simulation simply by simply saying “Look at the children”, we saw Bill and Nardole discover the truth as a CERN scientist asks them to say a bunch of random numbers and learn, not only were they both saying the same numbers but the scientist was also predicting the numbers correctly. It was a very dark moment in the episode, further added by the fact the scientist was simply killing time until the bomb he’d set to kill himself went off.

This horror was only added to by the presence of the Monks; the alien masterminds behind the simulation. They showed a surprising amount of cunning for Doctor Who villains. Why invade the world unprepared when you can practice and make invading Earth a fine art? And their confirmation that every simulation they’ve run has ended successfully with Earth’s last defence, the Doctor, dying is certainly a very chilling thought. How can the Doctor hope to defeat a foe that has already perfected defeating him countless times? In essence, this makes the Monks the Doctor’s most dangerous foe yet by default. Let’s not even factor in that the Monks were actually scary, silently creeping around, talking without really talking. A sequence where a blind Doctor stumbles around the Haereticum trying to avoid the Monks who he can’t see or hear is practically chilling. If the next two instalments of this three part story use the Monks just as effectively, they will easily emerge as one of Steven Moffat’s best creations.

But this episode was perhaps most notable for the revelation of who is in the vault the Doctor has been guarding. And it’s none other than the mistress of all evil herself; Missy. Seen in an extended flashback throughout the episode, we see just how Missy came to be in the vault. Captured for an unknown crime, Missy is due to be executed by the Doctor’s hand as per custom on the planet (the executioner must be of the prisoner’s own species). The Doctor takes an oath to guard Missy’s body for 1000 years but does not kill her, instead locking his oldest friend in the vault. Michelle Gomez was at once a delight as the evil Time Lady and comfortably steps back into the role despite being absent for 17 episodes. Gomez plays the character with utter glee, yet also an emotional side as we see Missy truly afraid for the first time. The woman who faced certain death twice without barely flickering an eyelid being so utterly afraid was a powerful moment and Gomez did perfectly. If there was ever any doubt that Gomez was the perfect Master, then let it be erased with this episode. With the Doctor realising he may need Missy’s help to defeat the Monks, it looks like we’re going to get even more Missy over the next two weeks. And more Missy is never a bad thing. As the villainess herself would say; “Oh Missy you so fine, you so fine you blow my mind, hey Missy! Hey Missy!”

The episode was helped brilliantly by a wonderful performance from Peter Capaldi. With the Doctor still blind after the events of Oxygen, Capaldi took the Doctor to a slightly different place this week. Seeing the Doctor try and keep his general attitude of “walk about like you own the place” without actually being able to see where he is was a fascinating idea to explore and Capaldi brings it to life spectacularly. The Doctor’s brazen overconfidence that his blindness means nothing while hiding it around others, only for the shield to crack when alone showing him to be just as terrified as most of us would be if we lost our sight was engaging to watch. The episode’s ending, seeing a terrified Doctor clutching the door to the vault, terrified that his beloved Earth is in danger and his blindness, being “lost in the dark”, may be what stops him from being able to defeat the Monks was a truly powerful moment.

All this would not have been possible without a truly amazing script by Steven Moffat. Moffat has proven time and time again that no one quite “gets” the show like he does and Extremis is another impressive addition to his already glowing Doctor Who CV. Much like Listen and Heaven Sent, Moffat brings the Doctor down and utterly breaks him with true fear and it’s the scenes where the Doctor is alone, when he has no one to be the “Doctor” for, where the episode truly shines. Moffat also sprinkles some truly excellent dialogue throughout (the Doctor’s “Super Mario” analogy is a standout) along with some truly hilarious jokes such as the Doctor saying he might get a reading chair with shackles as he might be able to finally finish Moby Dick with one and of course the Pope bursting in during the middle of Bill’s date, all of which leads to another belter of a script and easily the strongest of the series so far.

Extremis is one of those Doctor Who episodes that comes along every once in a while and reminds me why I love this show so much. It’s funny, it’s scary, it features some truly wonderful writing and performances, and it’s tightly paced and never feels rushed. It also poses some truly deep philosophical questions that will linger in your head long afterwards along with some fascinating and terrifying new monsters. Not only is Extremis the best episode of Series 10 so far, it might actually be one of the best episodes period.

10/10

Trivia and Speculation:

With this episode, Bill is now the fourth companion in a row to be trapped in a fake world. Donna was trapped in a simulation in 2008’s Forest of the Dead, Amy was trapped in a dream world in 2010’s Amy’s Choice and Clara was trapped in a dream world in both 2012’s Asylum of the Daleks and 2014’s Last Christmas.

Italian/English actor Joseph Long plays the Pope in this episode. This is not his first foray into the Doctor Who universe. He previously played Rocco Colasanto, the jolly and kind hearted Italian who, along with his family, was a fellow refugee with Donna Noble and her family after the destruction of London and ended up in forced housing with her in Leeds in 2008’s Turn Left, set in a parallel universe where the Doctor was dead.

The Doctor interrupting the first dates of his companions seems to be a habit. He previously interrupted Clara’s first date with Danny Pink (multiple times) in 2014’s Listen.

River Song’s diary makes a reappearance, presumably recovered from the Library where the 10th Doctor left it in 2008’s Forest of the Dead (coincidently another episode that dealt with characters trapped in simulations).

The Sonic Sunglasses make their return here, last seen in 2015’s The Husbands of River Song.

Missy mentions that the word amongst the Daleks was that the Doctor was living in domestic bliss on Darillium, as seen in The Husbands of River Song. When Missy was last seen she was cornered by the Daleks on Skaro in 2015’s The Witch’s Familiar.

What crime did Missy commit that led to her being captured and sentenced to death, and would lead to the Doctor being fine with her dying? Perhaps Missy has killed someone close to the Doctor? Or has committed an unforgiveable offence against him?