The Husbands of River Song (TV story)

The Husbands of River Song was the 2015 Doctor Who Christmas special. It was the show's eleventh Christmas special since its revival, and the second Christmas special starring Peter Capaldi as the Twelfth Doctor. It saw Alex Kingston return to reprise the role of River Song once more.

It was noteworthy for closing the book on River Song's timeline that began with her debut. It also showed the Twelfth Doctor's first encounter with River. For River, this was the final adventure with the Doctor before she met her demise in the two-part television story Silence in the Library / Forest of the Dead. This episode also revealed that it was the Twelfth Doctor who turned up on River's doorstep with a new haircut and a suit, their night on Darillium to see the Singing Towers, and the Doctor giving River his sonic screwdriver, all of which had been previously mentioned by River in the character's debut story.

In The Time of Angels, River stated that she had "all [the Doctor's] faces". This is proven true, for the Doctor's original regeneration cycle at least; this even included a picture of the War Doctor, whom the Ninth, Tenth and Eleventh Doctors all tried to keep buried in their memories of the Time War.

The Doctor takes River's assistant, Nardole, with him after this story as his companion. River's passing would also continue haunt the Doctor for some time, right into the next year's Christmas special The Return of Doctor Mysterio.

Synopsis
The Twelfth Doctor is on the planet Mendorax Dellora in 5343, where he is asked by a man named Nardole to follow him, thinking he is a surgeon, on the orders of River Song. A surgeon is required to remove a diamond from the head of the tyrannical King Hydroflax from a ruthless act of thievery gone wrong, and River seeks to recover it. Surprised that River cannot identify his newest face, the Doctor struggles to break the news to her while learning how she acts on her own- and how many other lovers she has had. However, both he and River soon find that the time is drawing close for the last page in the diary of their journeys together to be written...

Plot
On Christmas Day, 5343, on the human colony of Mendorax Dellora, Nardole finds the TARDIS parked and knocks on the door. The Doctor opens the door, asking if there is something on his head; Nardole confirms that there are antlers on the Doctor's head. The Doctor closes the door, yelling at the TARDIS for trying to cheer him up with holographic antlers. He opens the door again, with Nardole asking if he's the surgeon; stating it's close enough, the Doctor is told that he's needed. He asks if there will be caroling, to which Nardole denies.

They take off with Nardole explaining that they weren't sure where his "capsule" would land. The Doctor states it's a common thing for him, before stating he's had a bad day of "people turning into lizards" and a piano falling on him. As they pass the street, and elderly man with a bag asks a citizen if they were looking for a surgeon; obviously Nardole went the wrong way. Nardole brings the Doctor to a crashed spaceship.

A cloaked woman exits the ship, asking who the Doctor is. Noting the Doctor does not look like the surgeon's photos, the Doctor jokes that it's an on-going problem. Sensing that the woman is familiar, the Doctor asks if they've met. She states they have not, removing her hood to reveal herself as River Song. Smiling, the Doctor says her name. River is shocked he knows her name, asking how he knows her. The Doctor laughs, stating it would take a flowchart; however, River doesn't take the hint. Nardole tells the Doctor that he must refer to her as Dr. Song, or Prof. Song. Annoyed, River tells them to never speak her true name again or she will remove their organs in alphabetical order. Amused, the Doctor asks which alphabet. River scowls and head back inside.

Heading inside, the Doctor asks what the emergency is. River states that it's her husband. The Doctor is shocked, asking her to repeat that. River responds that her husband is dying. Stopping in his tracks, the Doctor is asked by Nardole if he's alright; not too pleased to hear River is married to someone other than him, the Doctor states "I'm going to need a bigger flowchart."

River leads him to her dying husband, King Hydroflax. To the Doctor's disgust, Hydroflax recalls having many romantic nights with River. Due to the guards being genetically-engineered to have anger problems and sentient laser swords, Nardole tells the Doctor to not do anything upsetting, like crossing his arms; the Doctor tells Nardole that he's got cross arms, crossing them anyway. River then tells Hydroflax that she called in the best surgeon in the universe to save his life.

The Doctor tells Nardole that he made a mistake, quietly; he tells him not to "make puddles". Seeing he has no choice by to help, the Doctor approaches to study the patient, being told bow in the king's presence. However, the Doctor states he cannot do so because of his back. He examines Hydroflax, determining that something is jammed in his head. River takes him to an adjacent room to discuss the operation he is supposed to be performing.

River shows the Doctor a holographic x-ray of Hydroflax's head, which reveals that the Halassi Androvar, the most valuable diamond in the universe, has become lodged in Hydroflax's brain during a raid on the Halassi Vaults and is slowly killing him. Having been hired by the Halassi to recover the lost treasure, River posed as Hydroflax's nurse and pretended to love him. River wants "the surgeon" to remove Hydroflax's entire head, considering it quicker and easier. "I'll kill the lights; you kill the patient." The Doctor is shocked by River's behavior, wondering if this is what she's like without him to keep her homicidal tenancies in check. He states that he'll decide what needs to be done because he's the Doctor; however, River doesn't get this obvious hint about his identity. Instead, River states he reminds her of someone; the Doctor starts to describe his last incarnation, but River exclaims that it's her second wife that he reminds her of. They are interrupted by Hydroflax who has listened to their conversation. Hydroflax reveals he is nothing more than a head on a mechanical body. River notes she thought it was strange they never shared a bathroom. He demands to know who his wife really is; River tells him that she's Professor River Song, archaeologist hired to retrieve the diamond and give back to the people he's taken so much from. She's even got a sonic trowel. While River defends herself the Doctor grabs Hydroflax's head and threatens to put him in the garbage disposal, creating a stalemate and allowing Ramone, River's contact, to teleport her and the Doctor.

The two end up in the snow, laughing at the ridiculousness of being threatened by a bag, which has Hydroflax's head in it. The Doctor now thinks River was just messing with him, asking if she really does know who he is. River states that she does not, as Ramone arrives; River pulls him into a kiss. The Doctor wonders "doesn't [kissing] get boring? It's not a varied activity." River reveals Ramone is her (third) husband, whose memory she wiped of their marriage because he was getting annoying. The Doctor sarcastically asks if she's going to murder him as well.

Ramone informs River that he has not found Code Name: Damsel in Distress, despite his capsule being in the village. River asks Ramone if he's sure as he does have twelve faces. Ramone unfolds twelve pictures, which are of the First, Second, Third, Fourth, Fifth, Sixth, Seventh, Eighth, War, Ninth, Tenth and Eleventh Doctors; he adamantly states that none of these men are in town. River is flabbergasted as she crashed Hydroflax's ship in this location because it's where she had the best chance to meet up with the Doctor. Decided to tease River, the Doctor states that he may have a face she doesn't know about; knowing the Doctor wasted a regeneration, River states that he has "limits."

Oboard Hydroflax's ship, his body decides to upload information about River Song from Nardole; it does so by decapitating him and placing his head in place of Hydroflax. It now has the information about where the TARDIS is located and that River is known to be assassinated with it.

The Doctor follows River and Ramone to the TARDIS, where River states she'll just borrow it. Taken aback by this, the Doctor notes that "Damsel" sounds dangerous and might be angry with her for stealing his ride. River states that he's never noticed before when she borrowed the TARDIS and put back where it was before, so why would she worry about it now. Aggravated to hear this, the Doctor states that he'll start noticing NOW. River sends Ramone off to get ready for their beach holiday. She heads inside, telling the Doctor that it's not as snug as it seems inside. Seeing it's "his turn" to play the shocked companion, the Doctor pretends to be shocked by the "bigger on the inside", giving a better monologue than others. The Doctor is then shocked to see that River turned one of the roundels into a cupboard for alcohol. Outside, Ramone hears Nardole call for help. He finds the robot holding Nardole at gunpoint, demanding that Ramone deliver a message to the former queen River Song.

Inside the TARDIS, River preps things for taking off. The Doctor learns to his shock that a button he usually uses doesn't help pilot the TARDIS, but instead causes the waste tanks on Deck 7 to be released. Deciding to avoid Deck 7 for a while, the Doctor watches as River tries to take off. With her confused, the Doctor reveals that the "real time" envelope cannot be sealed as the TARDIS registers Hydroflax as inside and outside at the same time. Being called good for a doctor, the Doctor is annoyed River still hasn't figured it out.

A knocking is heard on the door, with Ramone yelling for River. River opens the door to find Ramone's head on the robot body. It starts attacking, with the Doctor grabbing Hydroflax's head. He threatens to send Hydroflax down he trash shoot if he doesn't "get himself under control." This works, with River piloting the TARDIS to land in the starship Harmony and Redemption, where River requests that the Maître d', Flemming, deadlock seal the baggage hold in order to prevent Hydroflax's body from pursuing them further. River also reveals that she's 200 years old, thanks to augmented her lifespan.

Rather than return the diamond to the Halassi, River reveals that she intends to sell the diamond; the Doctor is surprised as she was hired to bring it back. Laughing, River asks if the Doctor was born boring or he had to work to be so. The Doctor notes that Deadlock seals can be broken; "by geniuses" River retorts, and a robot body isn't going to be one. Seeing River reading her diary, she sadly notes that the one who gave it to her knew how long it should be; there are only a few blank pages left for her to write in. River stops talking as a buyer named Scratch arrives, asking for the diamond. Scratch opens his head, pulling out an orb that connects to every bank in the universe to pay her. River hand him the bag with the head in it, telling Scratch he'll have to dig for the diamond. Annoyed, he reveals that he filled the meeting point with members of his own species to ensure honest transaction.

After receiving payment, River and the Doctor discover that Scratch and his compatriots worship King Hydroflax and are after the diamond in his honour. Despite attempts to hide the bagged head containing the diamond, they are forced to reveal the truth to create a distraction. Though it's considered heresy to try paying for the king, the Doctor laughs "He can't be much of a king if you can't put a price on his head." They toss Hydroflax away and flee, only to be stopped by Flemming, who was tricked into entering the baggage area by an under-duress Ramone. Sensing that Hydroflax's head is beyond recovery and will die imminently, Hydroflax's body destroys it, leaving only the diamond.

Flemming takes River's diary, explaining it is a guide to the best replacement head in the universe: the head of the Doctor. Scratch backs this up as the Doctor is a legendary being with multiple faces, which would be Hydroflax's crowning achievement; why they still consider the robot the king is bizarre. River is asked for the whereabouts of the Doctor, but she explains that although she loves the Doctor they are mistaken in thinking that he loves her enough to find himself with her, as she believes the Doctor to be incapable of falling in love. Seeing the steady gaze and mild smirk on the Doctor's face, River realises he's been with her all along and the Doctor confirms this by saying, "Hello, sweetie."

Being a time traveller, River is aware that the ship is about to be crippled by a meteor strike, which she uses as their escape plan, taking the diamond in the process. River chose this place based on a guide book that tells when to get a free meal at a restaurant when time traveling. The Doctor uses Scratch's universal bank transfer device to overload Hydroflax's body, before heading to the ship's bridge. While the ship is crashing, River realises that they are heading towards the planet Darillium - home to the Singing Towers mentioned by the future River as the place where she spent her final night with the Doctor. The Doctor retorts "I'll make sure to give them a wave as we pass by." Realising that they're unable to save the ship, they flee back into the TARDIS, but the impact of the crash knocks River unconscious.

After avoiding taking River to Darillium for as long as possible to avoid their last date together mentioned by her future self, the Doctor decides to give in to the inevitable. After travelling to the next morning, the Doctor suggests to a man searching for survivors of the crash that he build a restaurant where they're standing, with a view of the Singing Towers, and gives him the diamond to fund its construction. Travelling forwards in time once again, the Doctor enters the now-built restaurant and books the table on the balcony for Christmas Day in four years' time. When River awakes, she is told that the Doctor is waiting for her at their table. Changing for the occasion, River runs into Hydroflax's body, now peacefully controlled by the heads of Ramone and Nardole, was pulled from the wreckage and put to work as a waiter in the restaurant. River shows attraction to Ramone's new body, but is told to calm down by the Doctor, who has arrived in a new suit. River compliments him, to which he tries to return the favor. However, River notes that her husband never knows when she looks good, but it was kind of him to try. The Doctor gives her a box, with contains the sonic screwdriver she will use in the library; "I saw the sonic trowel, and thought it was embarrassing." The Doctor demonstrates it to River, discretely scanning her into the neural relay hidden in it, so his tenth incarnation can upload her data ghost into the virtual world in the Library computer. As the pair admire the Singing Towers, River notices the Doctor is crying, something he blames on having wind in his eyes. River reveals that her diary is nearly full, and asks whether the stories that this will be their final night together are true, to which the Doctor only responds by saying, "Spoilers": after knowing River for so long he had finally caught up with her in his timeline, and can't bring himself to reveal that this would indeed be their final night together. River begs him to find a way around this event, but he insists there's no way to avoid the end of their times together and refuses to tell River the future. They both discuss the fleeting nature of things, River pointing out that "happily ever after" does not mean "forever", just "time".

Fearful that not much time is left before they part, River asks how long a night on Darillium is. Smiling, the Doctor informs her that one night on Darillium lasts for twenty-four years. Overjoyed, River once more tells the Doctor, "I hate you." He again replies, "No, you don't." As the two smile at each other, the words "And they both lived happily ever after" are displayed on-screen. Little by little, the message dissolves into gusts of snow, becoming more truthful as it gets reduced to "And they both lived happily", then only "happily", until it has all been swept away.

Cast

 * The Doctor - Peter Capaldi
 * River Song - Alex Kingston
 * Nardole - Matt Lucas
 * King Hydroflax - Greg Davies
 * Ramone - Phillip Rhys
 * Flemming - Rowan Polonski
 * Scratch - Robert Curtis
 * Concierge - Anthony Cozens
 * Alphonse - Chris Lew Kum Hoi
 * Receptionist - Nicolle Smartt
 * King Hydroflax's Body - Liam Cook
 * Voice of Hydroflax - Nonso Anozie

Uncredited cast

 * Starline Galactic Villain - Clem So

The Doctor

 * The Doctor mentions that his eleventh incarnation had a big chin.
 * River Song suggests that the Doctor would not approve of alcohol aboard the Doctor's TARDIS, or would not approve of her taking the alcohol while she borrows the TARDIS.
 * The Doctor still enjoys mocking archaeology, referring to River's sonic trowel as "just embarrassing".
 * The Doctor mentions Euclidean geometry.

River Song

 * River states that the Doctor has planned to take her to Darillium numerous times but has always cancelled at the last minute.
 * River references her father, Rory Williams, by pointing to her nose (Rory had a prominent nose) and stating "Don't tell dad" while offering alcohol to the Doctor.
 * When searching through her bag at the beginning of the episode, River pulls out a red fez. This is a reference to the 11th Doctor, who sometimes wore a fez.
 * River Song owns the book History's Finest Exploding Restaurants with the tagline "The Best Food for Free, Skip the Coffee". She used it as a source when plotting her escape from the meteor strike that hit the Harmony and Redemption.
 * River has a unique perfume spray that lets her change her clothes as she pleases.

The TARDIS

 * The roundels are once again used for storage purposes. In this instance, alcohol is inside a cupboard behind one of them.
 * The TARDIS is able to produce a pair of hologrammatic antlers for the Doctor.

Technology

 * The body of Hydroflax contains a split quantum actualiser, thus its power source is a perpetually stabilised black hole.

Sonic equipment

 * River Song owns a sonic trowel, as a reference to her being an archaeologist.
 * The Doctor gives River her own sonic screwdriver, which she will eventually take with her to her investigation on the Library.
 * The Doctor uses his sonic sunglasses and his new sonic screwdriver.

Music

 * At the restaurant on Darillium, a string orchestra plays "The First Noel".
 * "Hark! the Herald Angels Sing" is played on Mendorax Dellora.

Locations

 * The Harmony and Redemption intends to visit the Andromeda Galaxy next.
 * The Singing Towers of Darillium "sing" due to the flowing of wind through the numerous cave structures in the towers which harmonises with the crystal layer.
 * There are 4 billion people on Mendorax Dellora.
 * As their name suggests, the Shoal of the Winter Harmony are originally from Winter Harmony.

Story notes

 * This is the first episode of Doctor Who since the 2012 Series 7 episode TV: The Angels Take Manhattan, and the first starring Peter Capaldi, to not feature Jenna Coleman as Clara Oswald.
 * Gary Russell previously attempted to have the Twelfth Doctor and River meet in his novel Big Bang Generation, but as Steven Moffat set up The Husbands of River Song to be the Twelfth Doctor's first, last and only meeting with River before she sacrificed her physical body, Russell chose to replace River with Bernice Summerfield in the story.
 * This is the first Christmas episode to have no scenes take place on Earth.
 * This is the first time in a main story that Alex Kingston's name has appeared in the opening titles.
 * When River's sonic screwdriver is revealed as her present, an excerpt of the Series 4 soundtrack "Silence In The Library" is heard, foreshadowing the events to come in River's last adventure.
 * As Mels, River used the phrase "penny in the air" when someone was oblivious to something important, following up with "and the penny drops" when they finally figured it out, seen in TV: Let's Kill Hitler. Ironically, River is guilty of becoming the butt of her own joke for being oblivious to the fact that the Doctor is right in front of her until it is made indubitable.
 * This is the first time outside of mini-episodes that River has been in a story not to feature one of the Doctor's companions alongside her and the Doctor.
 * The little town set used for Mendorax Dellora appears to have been repurposed from the trap street set used in TV: Face the Raven.
 * A variation of The Doctor's Theme is played when River and Ramone discuss the "Damsel in distress".
 * No cast details accompanied the programme listing in Radio Times, which had the synopsis "When a crashed spaceship calls upon his help, the Time Lord finds himself launched on a chase across the galaxy. Greg Davies and Matt Lucas guest-star." However, the listing for the repeat on Boxing Day (26th December) included a cast list as well the same synopsis (but excluded the final sentence).
 * This is the first episode where both the Doctor and his companion are played by people over the age of 50.
 * River's pictures of the Doctors are screencapped from The Smugglers, The Two Doctors, Carnival of Monsters, The Hand of Fear, Resurrection of the Daleks, Mindwarp, Survival, Doctor Who, The Day of the Doctor, The Parting of the Ways, The Runaway Bride and The Bells of Saint John. 
 * The Doctor is heard to say "when the wind stands fair and the night is perfect, when you least expect it, but always when you need it the most, there is a song". Though he is referring to the Singing Towers in this context, his statement could also apply to River herself, either symbolically or as a compliment. This is due to his inclusion of the word "song", which is her last name. Moreover, "song" is another name for "melody", which the towers produce; River's birth name is Melody Pond, and her alternate name, River Song, is the result of her birth name being translated into the language of the Gamma Forests, seen in TV: A Good Man Goes to War.
 * The opening titles to this episode have several modifications. The cogs are accompanied by snowflakes. Like in TV: Last Christmas, the clock tunnel is icy, the names for the actors and show title appear/dissipate into snowy particles, the emerging rings have snowflake decals, and the TARDIS is covered in snow (except this time, the snow does not disappear mid-way into the sequence). The planets are also replaced by Christmas baubles.

Production errors

 * When King Hydroflax's talking head is resting on the console's telepathic panel, the panel is bending inward. When his head is removed, the TARDIS console is fine again. This is most likely due to the production staff having replaced the panel with a fake one, which would accommodate Greg Davies' head with comfort.

Ratings

 * BBC One Overnight: 5.77 million (29.4% overall audience share)
 * BBC America Overnight: to be added
 * Final UK ratings: 7.69 million

Myths

 * A fragment of Rigsy's portrait of Clara Oswald, which disintegrated at the end of TV: Hell Bent, is visible on the TARDIS door. Inconclusive: some viewers claim it can be seen, but it could also be snow. A special TARDIS panel was created for the portrait (and later featured in the Doctor Who Experience exhibition), whereas the regular TARDIS shell would have been used for filming the episode.
 * Clara Oswald would appear. False. Originated from speculation that Jenna Coleman might have filmed a scene before completing her work on Series 9 (similar to how Matt Smith filmed his cameo for TV: Deep Breath).

Filming locations

 * to be added

Continuity

 * The Doctor states a piano fell on him at one point. He once described psychic linking with him was liking dropping a piano on someone. (TV: Deep Breath)
 * Nardole calls River "Doctor Song", (TV: The Time of Angels, The Pandorica Opens, Closing Time, The Angels Take Manhattan) stating that she is also sometimes called Professor, (TV Silence in the Library, Forest of the Dead, The Angels Take Manhattan) but mainly Doctor, Song.
 * River tells King Hydroflax that he has "stolen so much from so many." When talking to the Eleventh Doctor about how much he means to her and the universe she gives a similar statement, that he has "done so much for so many." (TV: The Wedding of River Song)
 * Once again, someone comments on the TARDIS being bigger on the inside. (TV: An Unearthly Child, et al) This time, it is the Doctor himself to an oblivious River, doing so sarcastically.
 * River mentions her history of escaping. (TV: The Pandorica Opens, A Good Man Goes to War, The Wedding of River Song)
 * Flemming reads in River's diary that she has just been to Manhattan. (TV: The Angels Take Manhattan)
 * The Doctor quotes River by saying "Hello, Sweetie" and "Spoilers". (TV Silence in the Library, et. al.)
 * The Doctor uses his new sonic screwdriver. (TV: Hell Bent) He also uses his sonic sunglasses. (TV: The Magician's Apprentice et al.)
 * River owns a set of pictures of the first twelve incarnations of the Doctor, which she reveals to clarify that she knows what he looks like. She told the Doctor once that she had pictures of all his faces. (TV: The Time of Angels) This also confirms that River is aware that the War Doctor exists (whom the Doctor once tried to conceal), as she has a picture of him as well. (TV: The Name of the Doctor)
 * River's picture set of the Doctor's first twelve incarnations creates a continuity error, in that her first appearance, she questions the Tenth Doctor about adventures she had with the Eleventh. The pictures in her collection are in exact chronological order, contradicting the idea that she mistook the Tenth Doctor for a later incarnation because she did not know the correct order of his regenerations.
 * When arguing about their other relationships, River Song holds against the Doctor his marriages with Elizabeth I (TV: The Day of the Doctor) and Marilyn Monroe. (TV: A Christmas Carol) Additionally, she suggests the Doctor was involved with Cleopatra whilst the Doctor suggests she had a similar connection to Stephen Fry.
 * Roundels are once again used as a means of storage. (TV: Castrovalva et al)
 * River Song recalls the Doctor trying to bring her to Darillium. (HOMEVID: Last Night) She later mentions the actual trip to the Tenth Doctor. (TV: Forest of the Dead)
 * River Song's diary recalls previous encounters with the Doctor: "the Pandorica opens", (TV: The Pandorica Opens) a picnic at Asgard, (PROSE: Picnic at Asgard, TV: Silence in the Library) the crash of the Byzantium, (TV: Silence in the Library, Flesh and Stone), "Manhattan". (TV: The Angels Take Manhattan) Their time with "Jim the Fish" is also acknowledged. (TV: The Impossible Astronaut, GAME: The Eternity Clock)
 * River previously showed an ability to handle wiping-memory technology. (GAME: The Eternity Clock)
 * River's diary is almost full, and she is aware the Doctor would know just how many pages she needed when he gave it to her. (TV: Let's Kill Hitler)
 * The Twelfth Doctor gives River her own sonic screwdriver. This is the version seen during her investigation of the Library. He then proceeds to scan her, imprinting her image into the screwdriver so it can later be saved as a data ghost. (TV: Silence in the Library/Forest of the Dead)
 * At Darillium, River notes that the Doctor is crying. She will go on to recall this to the Tenth Doctor just before her final moments. (TV: Forest of the Dead)
 * River believes the Eleventh Doctor was the last incarnation of the Doctor because she knew his regeneration cycle was limited. (TV: The Deadly Assassin, et. al.) The Doctor briefly mentions that he got past this limit. (TV: The Time of the Doctor)
 * The Doctor mentions he had a "new haircut", is in his "best suit" (though River disapproves of it) and is made to turn up on River's "doorstep". He is later seen in a suit at Darillium (which River really does finds nice), all in line with what she tells the Tenth Doctor about the last time she saw him. (TV: Forest of the Dead)
 * The Doctor has avoided Darillium, and is shown to be tearful when he finally makes good on his final date with River. The Doctor has mentioned that he does not like endings. (TV: The Angels Take Manhattan, The Name of the Doctor, The Time of the Doctor, Hell Bent)
 * The Doctor once again rewards someone with the means to gain a substantial amount of money. (TV: School Reunion, The End of Time) Interestingly, several people who have encountered the Doctor around Christmastime have now found themselves coming into large sums of money. (TV: Doctor Who, Voyage of the Damned, A Christmas Carol)
 * River pulls a fez out of her bag, an item commonly worn by the Eleventh Doctor. (TV: The Big Bang et al)
 * Hydroflax is nicknamed "the butcher of the Bone Meadows". The Doctor and River once visited the location together. (TV: The Time of Angels)
 * River mentions the time when there were two of the Eleventh Doctor during one of the instances where the Doctor backed out of going to Darillium. The Doctor has also been promising River for ages that they would go to the Singing Towers of Darillium. (HOMEVID: First Night/Last Night)
 * The Doctor says "every Christmas is last Christmas", repeating what Clara Oswald's imagined version of Danny Pink said. (TV: Last Christmas)
 * River tries to plead the Doctor into thinking of a loophole to avoid their last outing together, but the Doctor reminds her that not everything can be avoided. There have been situations where the Doctor has been unable the change the outcome of tragic events (TV: The Waters of Mars, Vincent and the Doctor), and he has just gone through one of these situations. (TV: Face the Raven, Heaven Sent/Hell Bent) He also reminds River that times end because they have to. (TV: The Time of the Doctor)
 * As the Doctor talks about the Singing Towers, he uses the phrase, "when the wind stands fair" to describe an instance when the towers produce a song. After being uploaded to the Library, River uses this phrase to describe an instance where "everybody lives" (TV: Forest of the Dead), something the Doctor greatly treasures. (TV: The Doctor Dances)
 * The Doctor refuses to bow to King Hydroflax, making the excuse that his back is playing up. The First Doctor was unable to bow to Kublai Khan, citing that it was because his back was broken; however, in that case it was a valid excuse because his first incarnation was growing elderly and indeed suffering from pain trying to bend over. (TV: Marco Polo)
 * The Doctor is able to reserve a table for years in the future and arrive at the reservation in an instant. He previously pulled the same trick with Clara on Calbaron III. (COMIC: Planet of the Diners)
 * River wears a Santa-inspired coat. (COMIC: Who Who Who, Merry Christmas)
 * River owns a sonic trowel. (AUDIO: The Boundless Sea) Her paternal grandfather was a huge fan of trowels and always carried one too. (TV: Dinosaurs on a Spaceship)
 * The Doctor refers to River's sonic trowel as "just embarrassing", continuing his mocking of archaeology. (TV: Silence in the Library, The Impossible Astronaut)
 * River Song says "I hate you" to the Doctor and he replies "No, you don't", an exchange they have had before. (TV: Flesh and Stone, The Impossible Astronaut) Sounding a little more forgiving, she would go on to tell the younger Tenth Doctor "I hate you sometimes", to which he replied, "I know!" (TV: Forest of the Dead)
 * The Doctor once again finds himself wearing holographic apparel. However, this time he does not have control over it, nor wishes to actually wear it. (TV: The Time of the Doctor)
 * The Doctor utters the inquisitive, "Seriously?" which - though he may no longer remember it - was often uttered by Clara Oswald. (TV: Time Heist, Dark Water, The Witch's Familiar, et al)
 * The TARDIS gives the Doctor hologramatic antlers. Coincidentally, Wilfred Mott, who often wore reindeer antlers on his head during the Christmas season, was once aboard the TARDIS in TV: The End of Time.
 * The Doctor, prior to changing clothes towards the end of the episode, continues to wear the replacement burgundy velvet jacket gifted to him by Clara Oswald (TV: Hell Bent)
 * The Doctor hangs a sign on the TARDIS doors. Unlike the others, this one reads 'Carollers Will Be Criticised', not 'Out Of Order'. (PROSE: Amorality Tale, TV: The War Machines)

Home video releases

 * This story was released on DVD in 23 February 2016.

Video game adaptation

 * On the 16 February 2016, a Husbands of River Song level pack was released for the game Doctor Who: Legacy. It used ten non-dialogue levels to visually retell the episode's story.