It’s Christmas…and Clara hears something on her roof. Turns out it’s Santa, his elves and his sleigh (and offering a tangerine)….and also the Doctor arrives to take her away. He’s pretty convinced that Santa isn’t who he says he is.
Santa is played by Nick Frost, who you might remember from his films with Simon Pegg.
The Doctor and Clara then arrive at the North pole, at an antarctic research station, where several personnel seem to have been put in a comatose state by mysterious aliens known as dream crabs which latch on to their faces-ones that soon attack. However, Santa arrives in the “Nick” of time to save them. During this, the Doctor and Clara reveal the truth to each other-the Doctor didn’t find Gallifrey; and Clara’s boyfriend Danny is still dead-he didn’t return from Missy’s nethersphere.
Clara however, soon comes under the influence of a dream crab, sending her into a dream world where Danny Pink is still alive.
The Doctor, knowing she’s in danger from the crab, enters the dream world willingly, but it’s “dream” Danny who willfully lets them go, saying that Clara must accept his death and move on.
After Clara and the Doctor exit the dream, the Doctor begins to realize that it was a dream within a dream-that the research station is itself a dream caused by the crabs, and that Santa is in fact their shared subconsciousness fighting back. He then uses this to conjure Santa to rescue them and have them ‘wake’ from their dreams, which in turn causes the dream crabs to turn to dust. They’re mostly ordinary people.
Waking from his own dream, the Doctor rushes to remove the dream crab from Clara with the sonic screwdriver. However, when he meets her it appears she’s now elderly.
However, it turns out that this is yet another dream, and the Doctor finds the real Clara, who is still in her twenties. The two then resume their adventures in time and space. Santa was just a dream…or was he?