The 2016 Doctor Who Christmas special opens with the Doctor being mistaken for Santa by a boy named Grant. When he introduces himself as the Doctor and Grant asks which one, and he says the original, Grant says that he ought to be called Doctor Mysterio, which the Doctor likes. The Doctor gives Grant a special gemstone to hold, and Grant mistakes it for medicine. The gemstone uses power from the nearest sun to turn wishes into reality, and since Grant loves Superman comics, it turns him into a superhero.
The episode introduces a company called Harmony Shoal, which has a vault of brains that are aliens working to colonize Earth. The Ghost, a masked superhero, intervenes. The Doctor realizes it is Grant, who it turns out is working as a nanny, since being a superhero doesn’t pay. The aliens decide to try to acquire the body of the Ghost, the best Earth has to offer.
The Doctor realizes that the aliens are going to stage manage an alien invasion to create a panic that will send the world’s leaders seeking safety in Harmony Shoal’s safe buildings. The Doctor meddles so as to crash their ship before they are ready, and in the end Grant has to intervene – revealing his true identity to the woman he loves.Towards the end, mention is made of the Doctor being away for 24 years, and River Song’s death. The Doctor says, “Everything ends, and its always sad. But everything begins again, and that’s happy.”
It was a fun episode, with a better balance between comedy and drama than the show has sometimes maintained in the Moffatt era. Nardole seems a really fitting companion for the Doctor, and as has been noted, this is the first time in a long while that we have this rare occurrence of a non-human accompanying the Doctor in his travels.