NOTE: Full spoilers for this episode of, “Doctor Who”, including who is in the vault, are present in this review
Doctor Who rebounded pretty spectacularly this week, with an especially strong mystery that may just be a highlight for the current Series Ten at this point! “Extremis” presented an especially potent and shocking mystery for The Doctor, Bill and Nardole to solve this week, and fortunately, this one also didn’t end with an anti-climactic and easy resolution like the season’s previous episodes have. This feels like a mystery and a threat fully worthy of The Doctor, especially since it looks like a powerful new force is going to emerge past this episode!
Most exciting of all about this episode though is that it finally reveals just who The Doctor and Nardole have been guarding in the vault. As many fans speculated, it is indeed Missy/The Master inside the vault, being put in some kind of inhibited state as some kind of last resort for The Doctor, honouring an oath he made to a world of executioners. Missy being tried for her crimes in the wake of Series Nine was a great way to bring her connection to The Doctor up a level, especially when The Doctor rigs her execution device to merely knock her out, rather than kill her, as he nonetheless honours his agreement to watch over her body for a thousand years. Also, on an unrelated note, the executioners actually fleeing from The Doctor, despite The Doctor being blatantly unarmed, when they see how many ways he’s ‘died’ and always come back was a terrific moment!
Another important dimension to this Missy reveal however, which is told in a flashback style at gradual points throughout the episode, is that it explains how Nardole ended up in The Doctor’s company after the conclusion of the 2015 Christmas special, “The Husbands of River Song.” I guess the 2016 Christmas special, “The Return of Doctor Mysterio” took place before these events, but regardless, River Song apparently gave Nardole her journal, along with strict instructions to prevent The Doctor from doing anything drastic in the wake of her death. This effectively binds Nardole to The Doctor, while also providing a way to effectively honour River Song’s legacy, short of actually dragging her back onto the show. It’s a great bit of backstory overall.
As for this week’s proper Doctor Who mystery, it comes when The Doctor is paid a visit in his classroom one night by the Pope and various cardinals, who ask The Doctor to come to The Vatican to look at a certain document called, “Veritas.” Apparently, everyone who looks at this document has committed suicide, be they Vatican officials, scientists or presidents. The mystery of a document containing a truth so terrifying that all of the most powerful, intelligent and faithful individuals on the planet would all be driven to suicide naturally excites The Doctor, and honestly, it makes for a really strong episode hook for viewers too!
All the while, The Doctor is trying to hide his blindness from Bill and the cardinals, with Nardole navigating for him in a subtle, clever way. The Doctor’s blindness was actually used really intelligently here, not only for some predictably strong humour, but also since it prevents The Doctor from just reading the document immediately. The Doctor is using his Sonic Sunglasses to map the area around him, but they don’t allow him to see finer details like text or lights, which complemented the inspired use of the Sonic Screwdriver’s destruction in last week’s episode, forcing a smarter solution. Mind you, The Doctor has already ended up with a replacement Sonic Screwdriver, so the previous one being broken is pretty moot, but at least his being blind is used as a smart and logical obstacle, without tipping Bill or the cardinals off to it in the process.
Bill and Nardole end up separated from The Doctor when mysterious corpse-like monks start coming after them though, with both of them eventually discovering a sequence of portals that bring them to powerful and secure locations, including the Pentagon, CERN and the White House. The people inside CERN most notably then draw attention to Bill and Nardole somehow choosing the same numbers when asked to pick a random sequence, and the two flee right as the scientists are about to blow themselves up. This wonderfully built the tension of an already strong mystery, especially as Nardole is the one to put two and two together, even if it comes with grave consequences.
So what exactly is going on with this Veritas document business? Well, it turns out that the entire world that Bill, Nardole and The Doctor are in is a computer simulation, which Nardole confirms when he sticks a hand outside of the portals’ projections, discovers he’s not real, and thus immediately disappears. Bill then finds The Doctor at the White House, complete with a dead President, with The Doctor confirming that Bill also is not real. As Bill disappears, The Doctor meets with one of the monks to claim that he knows about the simulation, something that was created by a villainous alien force looking to conquer Earth. By running simulations and assessing Earth that way, they can invade it perfectly, and know about all of its defenses in advance. This was all wrapped up in an excellent tie-in to the events with Missy, where The Doctor speaks about virtue only being true when it’s done without audience, hope or gain, after Missy begs for her life. The fake, simulated version of The Doctor then uses his last moments to E-mail the information to the actual real-world Doctor, right before the fake Doctor is wiped out, mobilizing the real Doctor to call Bill into action to prepare for the coming menace.
This was a brilliant end to a brilliant mystery, catapulting Series Ten to an exceptional new high note in, “Extremis.” The big twist, the subsequent stakes and the capitalization of The Doctor’s lack of sight was all excellent, though even better was finally answering the question of just who is in that big, mysterious vault and why. The Doctor saving one of his greatest enemies, thus proving himself as the virtuous man doing something of no benefit to him, nor any positive recognition, was a surprisingly logical way to have The Master cheat death again. Not only that, but the idea of Missy being an ace-in-the-hole, possibly getting one final act of redemption before she inevitably regenerates into a new form (Michelle Gomez is leaving the show alongside Peter Capaldi after this season, strengthening this likelihood), is a very promising idea for the season’s climax. Now that we have the answer to what’s about to happen on Earth in the meantime, hopefully next week’s episode of Doctor Who can sustain this incredible momentum!