"There's a horror movie called Alien? That's really offensive - no wonder everyone keeps invading you"
New-era Doctor Who Christmas specials are often a mixed bag. Whether announcing "big" events (Christmas Invasion, The End of Time, or last year's Time and the Doctor), serving as romps with moments of melancholy (Runaway Bride, A Christmas Carol), or even...well...(Voyage of the Damned, The Doctor, The Witch, and the Wardrobe), Christmas means an extra dose of Doctor Who. This past week's Last Christmas is unusual in that it's not just a seasonal celebration....it's also a thematic touchstone.
You wouldn't be too wrong in believing this is "Episode 13" of Series 8 - in fact, many of the previous season's themes are resolved in this single hour. It's a nice bullet point to a season driven by two dysfunctional characters - a woman with a need for control who may find TARDIS life increasing addictive, and a man finally coming to terms with "who he is". It helps that Nick Frost's Santa Claus serves as a nice counterpoint - a recasting of a traditionally "nice" role that provides some well-needed humor (as well as a counterpoint to Capaldi's Doctor). Once we get towards the end, there's a pleasing resolution - and recasting - of the Doctor & Clara's relationship. It may be a bit less contentious in Series 9, but it will definitely not be boring.
(Yes, we do get some resolution for the Clara/Danny relationship. It's one of the most poetic, hard-rending scenes I've seen. But then again, I'm an easy mark for stuff like that. It's the most emotionally honest expression about grief and mourning I've seen in awhile....and is much better than the "Love is a promise" manifesto from Death in Heaven)
And now, for the plot, which is....well, many other reviewers have made parallels to Inception, but Moffatt gives the idea of dreams-within-dreams a nice, Whovian twist. It's also one of the few Christmas specials that feels like it really does take place around Christmas, and feels the most seasonal. (The two wise-talking elves don't hurt). This easily could have been a "normal" Who episode - and yes, this episode wears its influences on its sleeve like crib notes. (Best quote from the episode is stated above).
That "dreamy-weamy"-ness (as hinted above) is what makes this episode a cut above the usual Doctor Who Christmas special. Some people may claim it confusing, or even possibly above the heads of a Christmas Day viewer, but Last Christmas' script doesn't feel loosely tossed together. Containing frights, delights, and "feels" in equal measure, it provides one of the most satisfying Christmas-themed Who episodes since The Unquiet Dead.
(Yes, I'm well aware that episode three of the 2005 series was never intended to be a Christmas-only episode. But that's my opinion and I'm sticking to it.)
And if all of Series 8 was the Doctor figuring out who he was (or whether he was "a good man"), Peter Capaldi's Doctor comes on full bore. Often abrasive, somewhat alien, but deep within, a man aware of who he is and what he has to do. At the end, when....well, let's just say that for one of the first times, we see the Twelfth Doctor with a manic glee unseen since early Tom Baker/Season 25 Sylvester McCoy.
It's hard to write about this episode without spoiling it - yes, I know people have watched it, but there's so much. It's an episode that plays with the very tropes of Doctor Who. (Think of it as a "base under siege" episode that takes place on multiple levels). It serves as a final chapter for a season that has felt....OK, but never quite crackled as it did under Russell T. Davies. (Or Phillip Hinchcliffe. Or Series 7. Or name-your-own-classic-era-here).
Last Christmas is the best gift that Who fans could have received - a story that not only serves to hit holiday themes, but also reminded us of the reasons why the show engages us so much. It's not just "a good Christmas Doctor Who" episode - it's a good Doctor Who episode - period.