“Look at you, beaming away like you’re Father Christmas.” “Who says I’m not? Red bicycle when you were 12!” “What?” —Rose and the 9th Doctor, “The Doctor Dances”

“Father Christmas, Santa Claus or, as I’ve always known him, Jeff.” “There’s no such person as Father Christmas.” “Oh, yeah? Me and Father Christmas, Frank Sinatra’s hunting lodge, 1952. See him at the back with the blonde? Albert Einstein. The three of us together. Brrm. Watch out. Okay? Keep the faith. Stay off the naughty list.” —The 11th Doctor and a boy, “A Christmas Carol”

“Doctor, listen to me. You can’t die, you’re too, you’re too nice, too brave, too kind, and far, far too silly. You’re like Father Christmas, the Wizard of Oz, Scooby Doo!” —Emma, “The Curse Of Fatal Death”

The simplest way to describe “Last Christmas” is that it’s a terrifically scary Doctor Who thriller that thinks—more to the point, wants its audience to think—that it’s a whimsical, even throwaway Christmas special. In the jolly figure of Santa Claus and the rather more caustic figures of his two elves, this special tosses out festive frivolity to match anything on display in previous Steven Moffat Christmas stories like the great “A Christmas Carol” or the distinctly less great “The Doctor, The Widow, And The Wardrobe.” But those elements are, as we learn, only there to run interference for a story that recalls the terrors of Alien—a deeply offensive title, as the Doctor points out—and all the Doctor Who stories it helped inspire, including “Midnight,” “The Waters Of Mars,” and “The Time Of Angels”/“Flesh And Stone.” And, on either side of all those seemingly endless layers of dreams, “Last Christmas” offers a pair of crucial character scenes to serve as codas to the recent season: the innermost fantasy sequence between Clara and Danny and the reunion in reality between the Doctor and Clara. The cumulative result is one of Doctor Who’s very best Christmas specials. While it can’t quite match “A Christmas Carol” for sheer effervescence, “Last Christmas” might just surpass it in pure, mad ambition.

On some level, this year’s Christmas special feels like an extension of “Listen,” as here too Steven Moffat deconstructs many of his most familiar tropes. The Doctor tells us that the dream crabs can weaponize people’s own dreams against them, and this is an entire story that weaponizes the audience’s narrative expectations against them. The story’s setup—a polar research base having to resort to absurd measures to defend itself against aliens that are only dangerous when people think about them—is just textbook Doctor Who, mixing in Moffat’s particular fascination with monsters that embody childhood fears with the longstanding Doctor Who favorite of a base under siege. (Considering that particular strain of Doctor Who story is most closely associated with Patrick Troughton’s 2nd Doctor, the presence of his son Michael Troughton as Professor Albert feels particularly appropriate.) The storytelling formula is so familiar, in fact, that “Last Christmas” can just skip the extraneous backstory.

After all, we’ve seen this kind of story a dozen times before, so do we really need to know what the purpose of the base is, or what Shona was actually trying to accomplish during her one-woman dance party, or why the Doctor and Clara just happened to turn up there? As engaged viewers, we might be aware that these are loose ends, the kind that the show has trained us to rationalize away as part of the cost of doing business, particularly now that the revived show has nearly a decade under its belt; the apparent narrative shortcuts of “Last Christmas” aren’t so dissimilar from those on display in, say, “Time Heist” or “Mummy On The Orient Express.” This episode simplifies its storytelling with what appears to be a familiar Moffat maneuver. The crew’s repeated replies to the Doctor’s inquiries that it’s a long story has the ring of a fairly standard, if minor, bit of Moffat wordplay, with the reiteration itself serving to distract us from the lack of concrete answers. In other episodes, that really might be all there is to it. But here, our ready acceptance of this underexplained scenario is a sign that we as an audience have grown too cozy—a particular risk on Christmas day, to be sure—and that the Doctor, Clara, and everyone else are failing to ask the blindingly obvious questions.

It’s as though Steven Moffat has taken all of his well-worn authorial tics and turned them against his own creations, which is what makes “Last Christmas” such a fantastically effective subversion of what we expect a Moffat episode to be. Even an apparent weakness of the episode, namely the thin characterization of the base’s occupants, comes to make perfect sense as we learn that none of these people are themselves until the very end. Admittedly, this narrative decision so closely resembles a flaw that it ends up kind of being one. In particular, we learn so little about Maureen Beattie’s Fiona Bellows that the reveal that her real self is in a wheelchair doesn’t read as much more than an offhand throw-in. But there is at least one big success here, as both the script and Faye Marsay’s performance do a fine job of emphasizing how little sense Shona McCullough makes as a research scientist. Marsay brings out some genuine pathos in the final sleigh ride, begging to stay a little longer before returning to what she knows is a far blander reality. Part of this special’s success is that it manages to land some of those small emotional moments, a feat that eludes many of its yuletide predecessors.

Still, if we’re going to explore how “Last Christmas” plays with viewers’ expectations, we really need to talk about Santa Claus. (Or Father Christmas. I understand there’s a difference, but since the special doesn’t seem to care, I’m not going to either.) As the quotes up top indicate, Steven Moffat has been drawing connections between the Doctor and Santa for as long as he’s been writing Doctor Who on television, whether it’s comparing them, suggesting the Doctor is Santa, or revealing the two hang out together with Frank Sinatra and Albert Einstein. That last line from “A Christmas Carol” now feels like such an artifact of the particular whimsy that defined the 11th Doctor’s era, and the current incarnation does seem to exist in a less magically unbounded cosmos—I discussed this in more detail in my review of “The Caretaker”—but this Doctor, for all his grumpiness and his skepticism, never explicitly rules out the existence of Santa, leaving it only as a question for the humans around him to answer.

And that’s the real trick of “Last Christmas”: Even if Doctor Who is no longer quite the same show it was in the age of chin and bowtie, it’s still a program that prides itself on the fact that anything can happen, and the episode is careful to present Santa in a way that feels only a fraction too outlandish for Doctor Who. Santa and his helpers are just so damn matter of fact in how they explain away all the apparent impossibilities of their existence; the early line about how ridiculous it is that one’s parents would shower kids with presents once a year for no particular reason feels like a very Moffat-y reversal of logic. Shona’s interrogation of Santa is a masterclass of mounting absurdity, punctuated by Santa’s hilariously straightforward explanation that flying reindeer are a scientific impossibility, which is why he feeds them magic carrots. But before that, the notion that basic physics demand the North Pole be an actual, striped pole is funny, but it’s also just about possible to imagine that as something the Doctor has visited on some unseen jaunt—maybe not this Doctor, but his predecessor, certainly. Santa here is like the show has given flesh to all the impossibly whimsical unseen adventures the 11th Doctor was always talking about, and the existence of that precedent makes it difficult to entirely dismiss Santa’s existence.

So much of the credit here has to go to Nick Frost, who more than earns his equal billing with Peter Capaldi and Jenna Coleman. He manages to bring an edge and a coolness to his Santa without ever making it appear that he’s trying to be edgy and cool, as that would be death. He plays Father Christmas as though this is the real man behind the fairy tale, even as he gradually reveals that there is only the fairy tale, and that’s all there really needs to be. There’s about a million ways that this could have gone horribly wrong—and I’ll admit that most of them flashed through my mind as Santa popped into the TARDIS at the end of “Death In Heaven”—but Frost, ably supported by Nathan McMullen and Doctor Who stalwart Dan Starkey as the elves, finds just the right approach as a figure who essentially runs parallel to the Doctor himself. There are Doctor-ish dimensions to his performance, particularly in how he hints at a being far more ancient and wondrous than even his bearded, red-suited visage would suggest. Basically, Frost manages to take Santa, a figure who is a readymade caricature, and make him into a genuine character, one that the audience wants to be real because he already feels like he is.

The other big guest appearance in “Last Christmas” comes as more of a surprise, even if it’s not exactly a shock: After all, tonight’s episode could hardly serve as a fitting epilogue to the previous season without one last appearance from Danny Pink. One major criticism of “Death In Heaven” that I didn’t really pick up on in my review is how much the finale loses track of Clara, with her grief over Danny’s death and resurrection largely subsumed into the final showdown between the Doctor, Danny, and the Master. “Last Christmas” doesn’t necessarily try to dig out some deeper emotional revelation about Clara’s state of mind, but that too is by design. The key line here comes just after the two admit to each other that they lied to the other at the end of “Death In Heaven.” With nothing further to say, they shift back to the deadly peril at hand; just as the Doctor hesitates, Clara presses, asking him to just give her something to do. Maybe there isn’t any great truth to uncover here beyond simply giving Clara space to acknowledge how much she misses Danny, and how uncertain of what she should do next.

Danny and Clara’s scenes are simple ones, really, not offering much beyond a portrait of the domestic bliss that the two lost. Perhaps the most striking fact is how willing Clara is to ignore all the obvious clues that something is wrong in order to regain it, to the point that she tells the Doctor to wake up and leave her to die happy inside the dream. Samuel Anderson is as great as ever as Danny; much like Nick Frost, he splits the difference between a grounded portrayal of the “real” Danny and a more romanticized version of the character. And, much like Frost’s Santa, it soon becomes clear how meaningless the distinction is between real and fantasy. Maybe this is a too perfect Danny, one who tells Clara all that her subconscious brain knows that she needs to hear. Maybe, in some impossible way, this is the real Danny; after all, the Doctor does borrow Madame Vastra’s line from “The Name Of The Doctor” when he points out time travel has always been possible in dreams. Really, though, it doesn’t matter, as this Danny acts just as the real one would. However you slice it, that’s a tribute to the love Clara and Danny shared, and “Last Christmas” elevates the entire season by taking time to honor that relationship.

This all then leads to the sweetest takeaway from their scenes together, as Danny—who may just be a figment of Clara’s imagination, but if that doesn’t stop Santa, why should that stop him?—tells Clara that she should spend five minutes each day remembering and missing him, but that the other 23 hours and 55 minutes should be spent living life as much as she possibly can. The implication is that, before that moment, Clara could not help but be consumed by her grief, and that she could only look to the rest of her life—with or without the Doctor—to distract her from that pain. The next step is not to forget that pain, but rather to find the right place for it, to let it exist alongside all the other things that life has to offer, to find a way to look back while still moving forward. That’s part of what Danny is getting at when he gives meaning to the episode’s title, explaining that people get together at Christmas because there’s always the chance it might be the last time. It’s a sentiment that doesn’t quite line up with the rest of the episode, at least not as perfectly as “halfway out of the dark” did with “A Christmas Carol,” but we get the best sense of it when both Shona and Clara try to linger in Santa’s sleigh: This is a magical time, one of reunions and remembrances, and it’s all so easily lost once the holiday is over.

The special’s use of nested dreams strongly recalls Inception, though it’s perhaps unsurprising that Doctor Who eschews the hierarchical precision that defined Christopher Nolan’s dream epic, choosing instead a far more anarchic path, employing far more switchbacks and fake-outs to keep even the Doctor guessing. The presence of the Doctor and the TARDIS does rather force that approach, as the Doctor himself observes that reality and fantasy are equally ridiculous. “Last Christmas” tiptoes around asking the really huge meta questions—there’s never any suggestion that the Doctor has somehow dreamed all 2,000 years of his life—but it does stress the essential impossibility of knowing when one is awake and when one is asleep, and Santa isn’t the only one to call out the Doctor’s own dreamlike preposterousness. This is where the episode delights in keeping the audience off-kilter: After all, monsters like dream crabs could only exist in a world that has beings like the Doctor, but are such monsters or such an alien really any more plausible than Santa Claus? That’s not a question with any easy answer, and the lone tangerine on the windowsill suggests.

There was a lot of speculation in the weeks leading up to this special that Clara would depart at its conclusion, and it’s only relatively recently that the tenor of the stars’ and production team members’ comments shifted so that it sounded like Clara would indeed stay. Indeed, at least one British tabloid—hardly a reliable source of information, but then not always an unreliable one either—reported that Jenna Coleman had planned to leave and changed her mind at the last minute, necessitating the hasty rewrite of a scene that saw an elderly Clara die in the Doctor’s arms. I mention this only because the knowledge of that rumor did color my viewing of the reveal and unreveal of the aged Clara. It’s certainly possible to see how that scene could have worked as an exit for Clara, giving her a more or less completed life and a final goodbye with the Doctor. And the final return of Santa is just sudden enough to believe that it is indeed the result of a last-minute rewrite. All of this is possible.

The thing is, I don’t think it really matters either way, because the ending works just fine, regardless of whether it is the original design or a hasty rewrite. Doctor Who’s Christmas specials tend to be melancholy affairs, with the Doctor either dealing with his own loss—“The Runaway Bride,” “The Next Doctor,” “The Doctor, The Widow, And The Wardrobe,” and “The Snowmen”—or suffering more losses along the way—“Voyage Of The Damned” and “The Snowmen” again. Only “A Christmas Carol” and the regeneration-focused specials really buck this trend. “Last Christmas” is maybe the best execution of this familiar yuletide formula, because it really means something for this most alien Doctor to reveal such human feelings, and Christmas is just the right crucible of emotions to bring that out. We’ve never seen this Doctor indulge in such daffy delight as when he takes the reins of Santa’s sleigh, but even that pales in comparison to what he shows us once he returns to reality (or what he thinks is reality). Peter Capaldi is on reliably fine form here, and he’s heartbreaking when the Doctor admits to the older Clara that he wishes he had returned far sooner, and he was stupid to have stayed away for as long as he did. In light of such sadness, it’s pretty much impossible to deny the Doctor the unadulterated joy that comes with that second chance.

This is what “Last Christmas” gets right, perhaps above all else. Steven Moffat’s script is inordinately clever in how it uses the trappings of a fluffy, silly Christmas special to crank up the scariness of a good old-fashioned monster story. But after all that, tonight’s episode manages something that not all of its Christmas predecessors manage, as it anchors its story in something that feels particular to the holidays. There is a melancholy to the comings and goings that define this time of year, and “Last Christmas” recognizes that from its title outward. But there’s also a chance for renewal, for miracles, for gifts. All of those speak to the fairy tale—or the reality, who can even tell?—of Santa Claus, and those are all things that the Doctor, and this Doctor in particular, richly deserves. And really, it’s all worth it just to see this Doctor look so completely happy. If there’s one thing we never really saw in Capaldi’s first season as the Doctor, it was the kind of unabashed joy that so animated the 10th and 11th Doctors and made the tail-end of the 9th Doctor’s journey—including his Santa claim to Rose at the end of “The Doctor Dances”—so powerful. Well, it takes the full hour, but “Last Christmas” gets us there. It was worth the wait.

Stray observations:

• “Last Christmas” makes explicit some things about the Doctor—or at least this incarnation—that have been hinted at before. I love the detail that he had already “deleted” the four researchers from his memory, and it’s rather sweet to learn that the Doctor legitimately can’t tell the young and elderly Claras apart.
  
• The Doctor and Santa’s argument over how best to describe what’s going on is a comedic highlight of the special; I could do with a lot more of Peter Capaldi and Nick Frost sparring in my life. Santa’s disgusted pronouncement that it’s all a bit “dreamy-weamy” is particularly nice.
  
• “You’re a dream who’s trying to save us?” “Shona, sweetheart, I’m Santa Claus. I think you just defined me!”