I'll admit it: This year's Doctor Who Christmas Special was a joy for me, feeling as if it was a distillation of everything I've enjoyed so far about the Steven Moffat era (Okay, with the obvious exception of no Rory and Amy, but still): Comedy, fairy tales and, of course, a big mystery at the heart of everything.

If anything, "The Snowmen" really drove home that Moffat's Who is at heart a mystery series. We've had mysteries running all through his seasons and arcs to date: What is the Pandorica? Who are the Silence? How will the Doctor survive his own death, which we've seen happen? Who is River Song? and so on. With an episode that made the most of its time period's obsession with Sherlock Holmes - and how interesting to see Moffat play with that quite so much, even to the point of having the Doctor claim that identity at one point, and then illustrate just how different he is from Moffat's other charismatic, long-faced hero - it only seemed fitting to introduce Clara and the mystery surrounding her, and use that to point out that that is what really drives the Eleventh Doctor: An inescapable love of figuring stuff out. Second only, I'd say, to saving the day.

Because, oh yes; this Doctor also loves to save the day. You could tell it, if you were looking, from his behavior while sulking (Compare the rudeness he had towards Strax and the way he acts towards him afterwards; the Doctor was performing his rudeness, it was an act that he wasn't even aware of, but one designed to attract a way out. The Doctor asking for help, without realizing it), or his lack of a snappy comeback when Madame Vastra teases him about having missed the danger and the excitement that came when the Ice Governess was attacking the home. It makes sense, of course; the Eleventh Doctor is much more consciously a children's character, and a children's protector, in part because Amelia Pond was the first person he met post-regeneration, and so it was the role that he landed in and was imprinted by.

(That reading also explains why he was so distraught by losing Amy and Rory; he sees himself as a protector, and he failed at protecting the first person - the primary person - he wanted to protect. Finally, it makes some sense.)

Into this, then, comes Clara. No wonder the Doctor falls for her - and he does, clearly; he's infatuated, something that's obvious even before she kissed him and he blushed. I wonder what River would make of this? - because she's very like him in many ways: Smarter than she lets on, endlessly curious and unafraid, sarcastic and moral and fiercely protective of those in her charge. That she is, in this guise, a play on another famous children's character (Mary Poppins, for those still curious) - feels particularly metatextual, but also right on considering all the Sherlock Holmes play going on. And, to top it all off, she's a mystery. Clara Oswin Oswald recurs throughout time, not just the person, but the things she bakes and the things she says ("Run, you clever boy… and remember"). But why? Reincarnation? Clones? A time loop? And is Clara even aware of this herself? After all, she says "remember," before she dies each time…

It helps, again, that Jenna-Louise Coleman has fun chemistry with Matt Smith; they spark off well against each other, and you want to see more of them together, even if the mystery leaves you cold… although why it would do that, I don't know; I love it, and am already curious about whether we're going to see a Clara die every episode until all is revealed when the show returns.

What else did I enjoy about the ep? The Vastra/Jenny/Strax pairing, again (That we saw them in the "Coming in 2013" tease was very welcome, but I still want that spin-off), the humor of the whole thing, and Richard E. Grant's pantomime sneers as the villain who wasn't what he seemed. I loved that it wasn't a particularly Christmassy episode, but felt very Christmassy, and I could not have been happier that it didn't just take the Doctor out of his post-Pond funk, but also sent him on a whole new mission that promises to excite, confuse and entertain in the months ahead. "The Snowmen" gave us a rebirth for the series in a way that made it seem as fun as it ever has, and I can't wait for what's in store in the show's 50th anniversary year.