The Return of Doctor Mysterio

At the beginning of the episode, the Doctor is constructing a device to reverse the paradoxes created during his previous visit in "The Angels Take Manhattan" (2012).[1][2] The Doctor mentions that he usually gets "an invasion" every Christmas, a reference to the different invasions of Earth taking place during most Doctor Who Christmas specials.[3]

The unnamed brain-swapping aliens last appeared in the 2015 Christmas special "The Husbands of River Song", where they were servants of King Hydroflax. Their main agent, Scratch, stated that they represented "the Shoal of the Winter Harmony."[2]

The Doctor tells Lucy that he works for Scotland Yard, which he also did in "The Woman Who Lived" (2015). Previously, the Tenth Doctor told the guests at Lady Eddison's manor he was a chief inspector from Scotland Yard in "The Unicorn and the Wasp" (2008), while the Eleventh Doctor told President Richard Nixon he was an undercover operative from Scotland Yard (code-named "The Doctor") in "The Impossible Astronaut" (2011).[2]

A cinema near Lucy's apartment features a film called The Mind of Evil, the name of a Third Doctor serial.[4]

Nardole mentions that the Doctor cut him out of Hydroflax's body, referring to off-screen events following "The Husbands of River Song" where he was decapitated and his head was placed inside the artificially intelligent robotic body of King Hydroflax.[5]

When the Doctor complains that Grant promised him never to use his powers, Nardole brings up the Time Lord policy of never interfering with other peoples or cultures, first mentioned in the Second Doctor serial The War Games (1969).[4]

When clearing out the headquarters of Harmony Shoal, a UNIT officer prepares to contact Osgood, referring to Petronella Osgood who previously appeared in "The Day of the Doctor" (2013), "Death in Heaven" (2014) and "The Zygon Invasion" / "The Zygon Inversion" (2015).[3]

Both the Doctor and Nardole refer to the final 24-year night the Doctor spent with River Song ("The Husbands of River Song") and her eventual death in the Library ("Forest of the Dead").[2]

The character of "The Ghost" is a pastiche of the comic book superhero Superman, with several references to the character being made throughout the special:

• Superman's creators, Jerry Siegel and Joe Shuster, are referenced when Mr Brock directs the gathered reporters to ask further questions of "Miss Shuster and Ms. Siegel".[6]
• Grant has roughly the same standard powers of Superman, including flight, super-strength, super-speed, being bulletproof, and possessing X-ray vision,[7] along with other unconventional powers.[1][7] He gains his abilities from a stellar-powered object (a gemstone made from a star, in the episode), much as Superman gains his from Earth's yellow sun.[1][7]
• The Harmony Shoals building in New York featured in the episode has a large globe on top of it, making it resemble the Daily Planet building, a major setting of Superman stories.[1]
• Grant prefers being called "mild-mannered", as Superman's alter ego is often characterized. He also follows the same moral code as Superman when operating as the Ghost,[7] and transforms in a similar fashion by tearing open his shirt to reveal his superhero costume underneath.[1]
• The special features a number of elements that mimic those from Richard Donner's Superman: The Movie. One scene involves the Ghost voicing his hope that Lucy's close call at Harmony Shoal hasn't put her off journalism, paralleling the same scene in the film in which Superman hopes Lois is not put off from flying after he rescues her from falling out of a helicopter.[7] Lucy also conducts a rooftop interview with the Ghost reminiscent of Lois' interview with Superman in the film.[8]
• Lucy Fletcher is named after Lois Lane's sister Lucy.[1] Her character is similar to Lois' in that she does not realize that her old high school friend and current nanny is the superhero Ghost.[5] The initials "L.L." used by several characters of the Superman comics (including Lois Lane, Lana Lang, Lex Luthor, Linda Lee, Lori Lemaris, Letitia Lerner, Lena Luthor and Lyla Lerrol) is used in Lucy's married name: Lucy Lombard.[1]

Several characters from Marvel Comics decorate the walls of young Grant's bedroom.[1] The Doctor questions Spider-Man's unusual origin of being bitten by a radioactive spider; he opines that radiation poisoning would be the likely result.[1] A "Joe's Pizza" is shown within the city, which is where Peter Parker worked briefly in the movie Spider-Man 2.[2] The Doctor counsels Grant that "with great power comes great responsibility," an adage associated with Spider-Man.[7]

Batman is briefly referenced after the Ghost drops Lucy off at her apartment building. When the baby monitor he is carrying goes off, Lucy mistakes it for a signal device and asks if the Bat-Signal is now an app.[1]

The Doctor uses the augmented reality game app Pokémon Go to create a distraction at Harmony Shoal's Tokyo headquarters.[9][10]

The episode received cinema screenings in Australia and New Zealand on 26 December 2016,[13][14] in Canada on 26 and 28 December 2016,[15] and in the United States on 27 and 29 December 2016.[16]

Professional ratings

Aggregate scores
Source	Rating
Rotten Tomatoes (Average Score)	7.89[21]
Rotten Tomatoes (Tomatometer)	89%[21]
Review scores
Source	Rating
The A.V. Club	B-[22]
SFX Magazine	[23]
CultBox	[24]
IGN	7.0[25]
IndieWire	A-[26]
PopMatters	5/10[27]
New York Magazine	[28]
Radio Times	[29]
The Daily Telegraph	[9]
SciFiNow	[30]
The Times	[31]
The Young Folks	8/10[32]

The episode received generally positive reviews from critics. It holds a score of 89% on Rotten Tomatoes based on 18 reviews, with an average score of 7.89. The site's consensus reads "The Return of Doctor Mysterio is a welcome return of Doctor Who after a year's absence, with the added fun of seeing Steven Moffat take a heroic swing at his version of a Superman story."[21]

The Daily Telegraph gave a positive review of five out of five stars and summarized that the episode was "a romp with a classic feel and cross-generational appeal".[9] Andrew Billen writing in The Times gave the programme four stars out of a possible five. Billen said that Capaldi was at his warmest and that Nardole (Matt Lucas) "added panto brio to an already exuberant episode".[31] The Guardian gave a positive review of The Return of Doctor Mysterio saying "Capaldi takes Manhattan!" ... "Cosmic baddies are inserting alien brains into world leaders’ heads in the Christmas special. It’s timely, top-of-the-tree fun – and Peter Capaldi and Matt Lucas are a pantomime treat".[33]

IGN said "“The Return of Doctor Mysterio” is a pretty lightweight entry in the Twelfth Doctor’s oeuvre, which considering the events of last season isn’t necessarily a bad thing. But the different elements of the episode don’t come together as smoothly as they could, and the emotional through line for the Doctor is treated mostly as an afterthought" but gave it 7.0 out of 10.[25] The A.V. Club gave a mixed review saying that "Doctor Who takes a jolly detour to superhero goofiness".[22]