The episode is set in New York City, and involves the Doctor and Nardole linking with journalist Lucy Fletcher (Charity Wakefield) and a superhero called The Ghost (Justin Chatwin) to combat brain-swapping aliens.

The only episode of 2016, it stars Peter Capaldi as the Twelfth Doctor, and is the first to feature Nardole (Matt Lucas), who was introduced in the previous Christmas special "The Husbands of River Song", as his companion.

On Christmas Eve 1992 in New York City, an 8-year-old named Grant wakes to find the Twelfth Doctor dangling outside the window of his home and helps him inside.

Dr. Sim, an employee already taken over, attempts to kill the group, when they are suddenly rescued by a masked superhero named the Ghost.

Lucy prepares for an interview with the Ghost, while the Doctor and Nardole track down the alien's ship in orbit and board it via the TARDIS.

Dr Sim lets slip the ship is to be dropped at a designated time; the Doctor forces its descent ahead of schedule.

[10] While planning for series 10 Moffat suggested that the Doctor should meet a superhero, executive producer Brian Minchin enjoyed the idea and proposed it for the Christmas special.

Grant has roughly the same standard powers of Superman, including flight, super-strength, super-speed, being bulletproof, and possessing X-ray vision.

[10] Nardole was innitally planned to be a one-off character though after Lucas stated he was interesting in returning to the role Moffat wrote him into the episode as well as the following series.

[14] Justin Chatwin and Charity Wakefield guest star as Grant Gordon / The Ghost and Lucy Fletcher, respectively.

[27] The episode's had an official rating of 7.83 million viewers in the UK, making it the 8th most watched show on Christmas Day 2016.

[29] It also received 1.7 million viewers on BBC America and became the networks top telecast of the year across all key demographics.

"[16] The Daily Telegraph gave a positive review of five out of five stars and praised the performance of Peter Capaldi and described the episode as having a fun "classic feel".

[26] The Guardian gave a positive review of The Return of Doctor Mysterio naming the episode "Cosmic baddies are inserting alien brains into world leaders’ heads in the Christmas special.