You open the presents, you devour the turkey, but the main event on Christmas Day is always the special hour-long dose of Doctor Who. Steven Moffat's third Christmas Special since taking charge of the show was arguably his best yet; featuring a beautiful Victorian London, terrifying snow villains, and an absolutely wonderful new(ish) companion, Clara Oswin Oswald.
Of course we'd already met Clara before. Back in the first episode of this series she was a soufflé-loving computer hacker stranded inside the body of a Dalek. But now we find her first a chirpy cockney barmaid, before after a short carriage journey she turns up at an elegant mansion a prim and proper governess. Her continual changes leave us constantly second-guessing who exactly she really is and what truly is her 'secret voice'.
"Winter is coming"
Tending for the two children of Captain Latimer, she notices that the pond where their late mother drowned has frozen over, and unlike the rest of the ice refuses to melt. Sadly this villainous frost wasn't the work of the Ice Warriors, but a parasite snow that mimics human actions. Unfortunately it imitates the misanthropic whims of the curled-lipped Dr Simeon, played with relish by Richard E Grant.
He commands an army of menacing-looking snowmen, a classic Moffat trope of turning the familiar into the frightening. The BBC was wise not to schedule the Snowman and the Snowdog on the same day. But for children watching perhaps the scariest monster was the frozen ghost of Digby and Francesca's mother, a constantly cross poltergeist imitating Mister Punch. Threatened by these frosty ghouls, she seeks the help of the Doctor. The only problem is he's retired.
The Adventures of Sherlock Holmes
Inspired by an unused Douglas Adams story, the Doctor has decided to dispense with policing the universe and retreat into the solitude of his TARDIS. After witnessing the heartbreaking departure of Amy and Rory in previous episode The Angels Take Manhattan, the Time Lord sees the prospect of losing any future friends too painful to contemplate.
But whilst residing in Victorian London, he's not completely alone. The dynamic detective duo of Madame Vastra and Jenny was bound to return at some point, though most fans will be disappointed that they haven't received their own Sherlock styled spin-off. Most of the humour in the episode comes from the Doctor's inexplicably still alive sidekick, Sontaran nurse Strax, expressing his fondness for grenades and full frontal military assaults.
"It's smaller on the outside"
But the true moments of magic in the episode come when Clara and the Doctor are together. Whilst most would scarper at the prospect of losing an hour's memory to an alien-worm, she stays by the Doctor intrigued to find out who he actually is.
The wonderful moment where she ascends the spiral staircase to the stars to find the TARDIS in the clouds is perhaps the most enchanting fairytale moment of the show to date. But Clara is not overawed by what she sees in the same way as other companions, inverting the usual perception of the TARDIS by noting, 'It's smaller on the outside".
"I never know why, I only know who"
Far from retreating into his shell, there is something in Clara that has made the Doctor want to come out of retirement and protect the world once more. Keenly grasping this new chance for companionship, he hands her the keys to the TARDIS saying, "I never know why, I only know who".
The dream is shattered straight away when the ice-woman grabs Clara and pulls her down to her death. But Clara seems to be a mystery that defies the normal conventions of life and death, seeing as we already saw her die once before back when she had been turned into a Dalek. Like Kenny in South Park, perhaps the running theme of the rest of this series will be seeing the Doctor meet a different Clara before she dies at the end of each episode.
"Run, you clever boy...and remember"
Meeting the same person again and again throughout time and space is an intriguing concept. Unlike River Song, a companion who was seeing the Doctor in the wrong order, here Clara is meeting the Time Lord each time anew, and yet she is fundamentally the same person.
The Snowmen focused on the power of memory and imagination, with a lifetime's worth of Dr Simeon's hatred memorised by the snow only for it to be defeated by Clara's tears at the end. In the same way that Amy saved the Doctor in The Big Bang by remembering him into existence, the Doctor will now journey to save Clara by holding on to his memories of her.
So much focus is put on the new companion that unfortunately the actual story, and the terrifying villains, spend most of the time sidelined. The idea of an alien force that mimics human behaviour is a great concept, especially suiting the Christmas theme where the monster manifests itself as Dr Simeon's Scrooge-like figure.
But that would be to miss the point the episode, which was to reintroduce a new companion for Matt Smith's Doctor to whet our appetites for the new episodes in 2013, the show's 50th anniversary. The mystery about her remains because even though we've met Clara twice now, we still don't know anything about her. It appears that for the rest of series seven the question that is going to be repeatedly asked is - Clara who?