Lost in Time (video game)

Doctor Who: Lost in Time is a licensed 2022 Doctor Who video game released for iOS and Android by Eastside Games. It was only released in a "soft launch phase" on 27 June 2022, with its full release being 8 March 2023.

The game was broken down into chapters with individual titles. The narrative, involving a mysterious temporal anomaly messing with the Doctor's memories, featured multiple Doctors and companions. However, it was not a conventional multi-Doctor story: the different Doctors never meet, with K9, newly-fitted with a vortex manipulator circuit, acting as a go-between.

It was an idle game, meaning gameplay consisted of little more than accumulating experience points via repetitive actions to unlock the next cutscene. The game also featured limited-time "Events", with varying time limits and some even featuring their own shorter storylines.

Publisher's summary
From the world of the beloved Sci-Fi franchise, Doctor Who: Lost in Time is an idle game where players join the Doctor in unraveling a sinister plot threatening the universe!

Power-up your Waypoint to obtain the mysterious Vortex Energy, a crucial force used to thwart the Doctor’s most fearsome foes.

Travel to classic locations from the franchise, and team up with your favorite companions! Together you’ll face enemies like the Daleks, Cybermen and many more! Collect character cards and use strange new resources like Kyfred Gems and Henoch Matter to level up your companions. These resources are key to discovering why the Doctor and friends find themselves lost in time.

When supplies run low, complete tasks to get Kerblam Boxes crammed with rare rewards. But hurry! With your enemies hot on your heels, you’ll need to tap as quickly as you can to power the TARDIS and travel to your next adventure, just in the nick of time.

Episode 1: Lost in Time
When the TARDIS is forced to make an emergency landing to the "nearest familiar spot", the Thirteenth Doctor and Yasmin Khan land in the Third Doctor's UNIT HQ laboratory. Making matters worse, the Doctor has no memory of the place, even though, by design, it should be familiar to her. The Doctor and Yaz are met with K9, who seems to understand more about the situation and explains that UNIT HQ passing through a black hole's event horizon created a "dimensional Waypoint", charging the building with Vortex Energy. The Doctor tells K9, who is able to move through time, to contact her other incarnations about the temporal crisis, and to pass on the message "Memory gaps. TARDIS is stuck. Send Vortex Energy!", collected from other Waypoints across space and time.

Indeed, elsewhere in time and space, others have been affected by the crisis. The Tenth Doctor's TARDIS has been pulled off-course to ancient Skaro, with Sarah Jane Smith aboard, and has gotten stuck there. Sarah is able to remember her past encounters with the Daleks, unlike the confused Doctor, but despite his mental fog, the Doctor is able to remember K9's message: the Dalek City has also become a Waypoint, from which he must draw vortex energy to revive his TARDIS.

At UNIT HQ, the Thirteenth Doctor succeeds in drawing sufficient power to unstick the TARDIS. However, she is worried that the unrefined vortex energy might cause power surges in the TARDIS console. Yaz jokingly advises her to "reverse the polarity" using the sonic screwdriver, a phrase she's heard the Doctor use before; it turns out to work, but to Yaz's surprise, the Doctor has no memory of using the phrase previously. The Doctor, Yaz and K9 get into the TARDIS and successfully take off, though they suspect they'll have to do it all again every time they want to take off again until such a time as the crisis is resolved.

Episode 2: Emergence of the Daleks
The Thirteenth Doctor's TARDIS lands. As predicted, K9 Mark IV notes that the trip depleted her reserves of vortex energy. K9 sends a message through time to the Tenth Doctor, still stuck in the Dalek City, to tell him that one of his future incarnations has freed themself and will try to send him spare vortex energy if they can. In the meantime, Sarah reminds the Doctor that, if his fourth incarnation's statement that the Daleks had been delayed for "a thousand years" was accurate, the Daleks shouldn't be free yet in the time-zone where they've ended up. Indeed, they hear Dalek voices in the distance.

Meanwhile, the Thirteenth Doctor and Yaz venture out into a marketplace where they meet Sil, who sells them a way to absorb vortex energy in larger increments. K9 then transports himself to the Dalek City. He proves a great asset, helping to automate the vortex energy collection process, and assures the bipeds that he is no danger from the Daleks: the smooth metal floors of the City are as ideally suited to his movements as to the Daleks', and he is faster. The Doctor additionally explains to Sarah that "since you last met", K9 has been upgraded, notably being given an internal vortex manipulator and a Temporal Positioning System. This is how he's been moving and communicating through time even with the Doctors' TARDISes partially disabled.

While K9 handles the vortex-energy collection, the Doctor and Sarah resolve to investigate how the Daleks have re-emerged so early in Skaro's history by getting captured by a Dalek patrol. This is quickly done, but the Dalek which apprehends them is a Time War-style Bronze Dalek, and the Doctor spots a Dalek Time Ship in the distance, realising that future Daleks went back in time to help their own ancestors. However, the temporal crisis has grounded the Dalek Time Ship too, stranding the future Daleks in their own past. Sarah suggests that the Doctor offer to help repair the machine, with the secret intention of sabotaging it while learning more about the Daleks' plans.

Episode 3: Home Is Where The Hearts Are
K9 has now dropped in on the Twelfth Doctor and Bill Potts, whose TARDIS is stuck on Gallifrey. He advises the Doctor to use "Matrix Representation Icons" and "adaptive neogenesis molecules", which the Doctor knows better as Waypoint Cards and Henoch Matter, to upgrade the TARDIS's generator workers' efficiency. K9 also states that he detected a nearby cache of Kyfred Gems, which the Doctor decides to "borrow" so as to be able to easily buy any equipment they may need along the way. After they recover the Gems, K9 has a better idea: to use them as temporal "skipping stones" in the space-time continuum so as to "refocus temporal energy". They decide to do it through the Untempered Schism, with the Doctor giving Bill a protective shield to wear to prevent it "melting her brain". They walk through the Panopticon and out beyond the Citadel. When they get to their destination, however, the Doctor suddenly gets a premonition and sends a message through K9 to Sergeant Benton that he may soon encounter "Clara Oswald, a.k.a. Impossible Girl", and should do his best not to interfere with whatever she's doing. Benton readily agrees, but forgets to ask who she is and how he'll recognise her before K9 disappears again.

Episode 4: The Right Place At The Right Time
Now being chased through time by a Dalek, the Twelfth Doctor's newly-functional TARDIS makes an emergency landing in Nevada. After getting a message from River Song through K9, the Doctor walks out and is confronted with Clara Oswald wearing an American diner waitress's outfit. He seems to remember her, but is very confused to see her alive. She explains cryptically that she is "here to save you. Again, I think, one last time". The Doctor, with his memories, is very confused, as is what turns out to be another Clara Oswald — an earlier version, travelling with an earlier version of the Doctor. Their TARDIS, drained of power by an unknown source, also crashed here.

The Dalek chasing the older Twelfth Doctor soon catches up with them. However, it is confused by the presence of two Claras, one of whom is only debatably alive. The younger Clara takes advantage of its confusion to talk it into self-destructing, drawing on her experience as a Dalek to convince it in highly Dalek terms that its time-travelling has splintered its DNA and made it an impure failure ("Impure! Impure! And you've failed your mission! You have failed! You have failed!"). When the Doctor comments that the scene was somewhat disturbing, the older Clara wryly notes that she's done "much worse" since. K9 interrupts the conversation, calling out to the Doctor to say that he has identified the next Waypoint: Stonehenge.

Episode 5: All The Better To Sea You With
Martha Jones, travelling across the stations of the Osterhagen Project with Project Indigo, ends up pulled off-course to Atlantis. Realising that she's ended up in the wrong place, she activates Project Indigo again, thinking to herself "There's no place like home".

Moments later, the Fourth Doctor's TARDIS lands in the same place. He walks out with K9 Mark I, who detects "redisual energy from a vortex manipulator". Before he can tell him anything more, K9 malfunctions. The Doctor realises that the time crystal is to blame, and that they've become stuck in a time eddy.

Episode 6: The Pandorica Prologue
When K9 Mark IV checks in at the UNIT HQ laboratory, Benton asks him if he can take a message back to the Doctor, whichever one is most readily available: apparently, NATO anti-submarine equipment has been "acting up", and the Brig is worried that it's "the Sea Devils again". K9 uses his vortex manipulator circuit to transport himself to the location of the Twelfth Doctor: the Underhenge at Stonehenge, the "Pandorica Waypoint". Just as the Doctor is explaining the nature of the Pandorica to the immortal Clara, they are attacked by a pair of Cybermen guarding the Pandorica. Though unarmed and not even remembering what Cybermen are properly, the Doctor puts up an unflappable front.

Episode 7: In All The Towns In The World
Jo Grant enters the UNIT HQ laboratory looking for the Doctor, only for Benton to explain that the Third Doctor and the Brig have been gone for a little while, having gone off to "some fancy shindig in Geneva": the United Nations are giving the Doctor an award for salvaging the peace conference "last January".

Elsewhere in time, a version of the Tenth Doctor is visiting ancient Atlantis with Martha Jones when he detects the presence of a vortex manipulator in a nearby temple using the sonic screwdriver. They rush there, and the Doctor is already rattling off the appropriate Shadow Proclamation warnings when the "tomb-robber" greets him with a "Hello, sweetie": it's River Song, who describes herself as the Doctor's wife. She explains that she intended to arrive literal moments before the sinking of Atlantis and rescue a "priceless artefact" which she intends to sell to the Lux Library Foundation. She is thus mildly confused to see that Atlantis is showing no signs of sinking. However, without further ado, she slaps a memory worm on the Doctor to make him forget the encounter and thus preserve the timeline, then dashes off.

Episode 8: A Deep One
Inside Clara's TARDIS, Ashildr moodily asks Clara Oswald if her meeting herself is going to turn into a regular occurrence. Clara explains that it shouldn't, normally, but that, since her splinters are widespread throughout the Doctor's time stream, their best course of action is to avoid running into the Doctor. According to her, they need to find someplace the Doctor would never go — somewhere exceedingly boring. Ashildr knows just the place, and they set a course for the Minyan ship.

Elsewhere and elsewhen, Atlantis, still in a time eddy, is being explored by Martha Jones in the company of a representative from the earlier version of UNIT: none other than Doctor Liz Shaw. They are confronted with a Sea Devil, who explains that their local Sea Devil hibernation pod was activated by the Doctors' vortex energy-collection, and have set things in motion to send out a signal that will awaken the millions of other Sea Devils hibernating around the world. Liz and Martha try to convince the Sea Devil to delay the awakening so that a peace plan between the reptiles and humanity can be worked out; the Sea Devil seems amenable, and Martha calls the Doctor for help. The Doctor arrives in the form of the Thirteenth Doctor, who begins negotiating with the Sea Devil.

Episode 9: Forgotten But Not Gone
K9 brings Rose Tyler to the Panopticon to meet with Sarah Jane Smith. Sarah Jane is just beginning to explain that she and her Doctor are drawing vortex energy from Skaro when they get side-tracked talking about how many times they've each faced the Daleks. Agreeing that the Panopticon is a risky place to meet, even with perception filters, they decide to move to a safer location to continue the conversation.

At the UNIT HQ laboratory, Jo is talking with Benton about the effort to recharge all the TARDISes when K9 appears and alerts them to the presence of an alien life-form somewhere within the space-time Waypoint, i.e. UNIT HQ. With a bit more data, the three realise that one or more Cybermen have reassembled themselves out of the broken parts stored in the UNIT Vault following the attempted Cyberman invasion of Earth. One breaks through into the lab, and K9 seems to have disappeared, but when it tries to capture Jo to convert her, she hits it in the chest with her golden bracelet, sending gold flecks into its respiratory system which prove sufficient to kill it. K9 returns to explain that gold is deadly to the Cybermen, clarifying that he had to teleport off to deal with other alien threats escaping from the Vault.

Episode 10: My Friend's Enemy Is Also My Enemy
Waiting for the Twelfth Doctor in the Panopticon, Bill is surprised to see Nardole, who she didn't know had been on the ship. He explains that the Doctor has told him to help with the vortex energy collection, hence his leaving the ship.

Meanwhile, the Fourth Doctor has returned to the Minyan ship P7E with Leela. He explains what he has learned from his future selves: Daleks from the early days of the Last Great Time War will attempt to attack the Minyans before they make it to their new home, afraid that, after being saved by the Doctor, they would return to being allies of the Time Lords. Indeed, the Minyans detect a Dalek ship, but the Daleks board them instead of initiating a space battle. After coming aboard, two Daleks explain that they are here for the Minyan race bank which they want to "study" and then return "undamaged". The Doctor guesses the truth behind this un-Dalek-like behaviour before they can trick the Minyans: the Daleks intend to alter the genetic codes contained in the bank, so that the future generations of the Minyans will be ontologically loyal to the Daleks. While the Doctor distracts the Daleks, Leela manages to get behind them and startle them; they fire at her, not realising that she is now carrying a Minyan shield gun, which she uses to reflect their gunstick-fire back at them, destroying them. The Doctor congratulates her on her "excellent use of geometry".

Episode 11: Welcome To The Neighbourhood
In Victorian London, the Twelfth Doctor drops in on Vastra, to help her deal with a Tyrannosaurus rex roaming London. She initially believes that it has been taken out of time, but the Doctor explains that it was actually sleeping with a colony of Silurians in a nearby hibernation facility, whose reanimation unit was accidentally activated by the Doctor's collection of vortex energy. Confronted with the T-rex, the Doctor tries talking to it and it turns around. While Vastra initially believes the Doctor's appeal worked, the Doctor notes that his sonic screwdriver detected a high-frequency signal being used to recall the creature.

Indeed, a trio of Silurians in full armour, calling themselves a Triad, arrive to confront them. They recognise Vastra and ask her where the rest of her "settlement" is, forcing Vastra to recall that there was "an accident" and she is the sole survivor of her group. The Triad are reluctant to consider peace, viewing the humans as nothing more than proliferating pests and explaining that they have already infected three prisoners with the Silurian plague, intending to release them at dawn to cause a devastating epidemic. When the Doctor thoughtlessly mentions in the Triad's earshot that he already developed an antidote to the plague long ago, they threaten to take the Doctor and Vastra as prisoners, forcing Vastra to stun the three with her tongue. She then takes them back to their hibernation facility, seals the tunnel auto sealer to prevent them from being released accidentally again, and reactivates the hibernation circuits. Meanwhile, the Doctor takes the T-rex back to Canada sixty-six million years in the past. Vastra approves, stating she never approved of "the practice of keeping wild animals as pets". The Doctor mentions that one of the three men the Silurians captured, whom he has now released, was a Mr Doyle who "said there might be a book in this".

Episode 12: If At First
The Minyan ship reaches their new planet, with the Fourth Doctor and Leela still on-board. Before they can begin the geomorphing, however, Leela gets a premonition of doom, soon fulfilled by the appearance of a further group of Daleks, intent on trying again to corrupt the race bank using the Mutation Device. While they activate the Device, the Daleks plant a ring of explosives around the valley where the Minyans have landed, threatening to detonate them and collapse the valley if anyone interferes with the Mutation Device. After the Doctor tells Leela about the Daleks' eye-piece weakness, she manages to blind one Dalek which begins to frenziedly fire in all directions and ends up taking out the other Daleks even as they exterminate it. However, the Doctor and the Minyan Tala are left wondering if the Daleks will try a third time.

Episode 13: Everything At Once
In a flashback to Skaro, the Tenth Doctor is surprised to detect the presence of free-floating symbiotic nuclei, an essential part of Time Lord biodata that isn't normally supposed to ever be seen outside of a Time Lord's body. Sarah Jane Smith suggests the Daleks could have lured and killed a Time Lord to the City, and extracted the nuclei from them; the Doctor admits that it's possible, but remains unconvinced.

In another flashback, the Twelfth Doctor, still in the the Underhenge, is joined by River Song. The two are confronted by the Lone Centurion himself, Rory Williams, but the Doctor barely registers the encounter, too busy trying to tap into "another dimension".

Back on the Minyan ship, prior to its landing on New Minyos, the Fourth Doctor is similarly distracted by what he describes as a time echo.

Back in the UNIT HQ laboratory, the Thirteenth Doctor finally remembers what she knew the place from, and also realises that "there is a fragment of [her] just beyond reach in a nearby dimension", namely her symbiotic nuclei. She guesses that there must be bundles of them overlaid over each Waypoint.

The Twelfth Doctor is coming to a parallel conclusion, and as he concentrates on it, his consciousness becomes almost completely untethered from linear time, with his awareness jumping between multiple incarnations.

On Skaro, the Tenth Doctor pursues his analysis of the symbiotic-nucleus traces, and discovers signs that the Master is involved. He heads back to the TARDIS, determined to track him down.

Episode 14: Not What You Know But Who You Know
Jo and Benton find out via the Thirteenth Doctor that the Master is involved, and she wants them to call her if he turns up and that she'll leave a note for the Third Doctor on what he should know.

Vastra shows concern on whether the Master shall appear in their location. The Twelfth Doctor doesn't think so but states its possible that Missy might, and that it'd be more personal than her Nethersphere plot.

River tells Rory to prepare himself for the Master though quickly realises he isn't familiar and never crossed paths with him, due to the fact Rory has spent the entire time simply guarding the Pandorica.

Martha and Liz Shaw are made aware of the Master situation, with Martha believing him to be dead, though the UNIT files state otherwise. The two had been told to capture the Master alive due to them needing information from him, but due to the file stating that he rarely repeats himself they may not have to expect him at all. Regardless, they'll be ready for him.

Sarah Jane and Rose also talk about the Master, with Sarah being aware of him but not having ever met just like Rose. They also talk about the elusive topic about the Doctor's family.

On Gallifrey, Nardole and Bill discuss the Doctor's belief that the Master is responsible for his memory mishap

Episode 15: The Dark Side Of The Moon
Kate inquires to Osgood as to why they can't raise Dome Seven which is due to a sphere found in a crater on the far side. Due to it being analyse in Dome Seven it can't be raised. As it turns out it's a Nestene Energy Unit and they are all in danger. As such Kate orders all personnel to stay clear of Dome Seven. Osgood suggests calling the Doctor, but him in his third incarnation is already there asking how much of the base contains plastic. Kate explains that almost everything does, with some of the domes being entirely 3D printed out of the material. She also states that the CCTV in Dome Seven shows three of their staff are dead which the Doctor seems to believe is due to exposure to the vacuum of space. Osgood interrupts by stating the airlock hasn't been opened but the Doctor is aware the Nestene Consciousness could have done a number of things to make that happen.

Things go from bad to worse as Dome Six's 3D printer starts by itself, which the Doctor says is printing Autons. He explains that one of the Energy Units has a small part of its consciousness stored in it but enough to cause chaos, and that their antenna will be the next target which they'll use to download more of its consciousness. After they take over the Moonbase they'll redirect it towards Earth. He asks to see Osgood's electronic stores.

The Doctor creates a device that's to be attached to the antenna to neutralise them, Osgood likening it to the jammer he built with Shaw. The Doctor tells Osgood to patch the link to the console and for her to be ready to activate it when he signals. Osgood volunteers to take his place due to him being more valuable to the Earth but the Doctor refuses, though would like a space suit for the occasion.

The plan is nearly finished, but the Autons are closing in on the Doctor. He combats them with Venusian aikido which was easy for him due to the extreme cold making their plastic bodies weaker. The plan works and the Autons all collapse, the Doctor asks for a shovel to rebury the Energy Unit.

Episode 16: Lunar Petri Dish
After having taken samples from the Energy Unit he discovers that there are atypical traces that should require further analysis. Kate ponders whether this group is from the original invasion group but the Doctor doubts it as they aren't known for mistaking mistakes or improvisation.

Kate was analysing data of their impact but the Doctor believes their landing was planned, as the coincidence of it being found near a moonbase that wouldn't be built for decades is troubling. Kate asks whether the Nestenes would know that a base would be built before even they did. Given the only possibilities are foresight and time travel - and they have neither - the Doctor and Osgood deduce they had help from someone who does.

Having completed tests, Osgood find traces of artron energy, meaning it has indeed travelled through time.

Back a the Pandorica, the Thirteenth Doctor is checking for Time Sense bits. She states there are lots of traces here from an earlier version of her. Yaz wonders if there's any sign of the Master, Dan unaware of who they are. She explains who the Master is to Dan though her memory fails her as she can't remember what they used to do. They return to the TARDIS.

Episode 17: Breadcrums In The Forest
In London Vastra offers to help the Doctor with his research if he helps with theirs. The Doctor explains he's losing time in shards and doesn't want to play detective, but Vastra states it is important. Jenny says that they suspect foul play as any physical traces vanish. Strax continues that no evidence can be found to suggest they were being dragged. The Doctor does a scan with his sonic sunglasses.

The trail directs them to an abandoned warehouse, though nothing is known about the owner of the building. The Doctor decides he's going in, despite the danger as Vastra protests. He responds by saying there's nothing more dangerous than him, so Vastra decides to accompany him. Strax and Jenny stay outside to guard the perimeter. The enter, the Doctor sensing a tingling and detecting the smell of copper in the air, meaning they entered a Transmat gateway disguised as the door to the warehouse. This has transported them to a Minyan ship, though there's something off about it.

Vastra claims to sense the stench of death in the air. They are then forced to hide as Daleks enter the ship desiring humans for experimentation, and that the plans obtained from the Time Lord time vessel must be completed.

Back on Gallifrey, the Fourth Doctor is telling Leela that Time Lords and their bureaucracy bore him. The reason for their visit it due to the library of Gallifrey potentially containing information about his current problem. They find a note for the Doctor, detailing that the Doctor is the writer's dearest enemy and it seems that he's finally won. It's clear that it's the Master but it appears as though he's suffering from the same condition that the Doctor is.

Episode 18: The Moons Of Skaro
On Skaro, Rose notices an extra moon in the sky. The Daleks are clearly concerned about it as their patrols have tripled. The Doctor boosts their perception filters so the Daleks don't spot them by accident. The Doctor uses his sonic screwdriver to find out what he can about the moon, and finds out it isn't one - it's a space station. A Cyberman space station, one that used to be a moon that was entirely cyber-converted.

The Daleks receive an incoming transmission from the space-station. The Cybermen demand information, ordering them to release the plans for the time ship. The two factions threaten to destroy the other.

To be continued

Episode 19: Jurassic Strife
To be added

Episode 20: Two's Company
To be added

Episode 21: Cold Storage
To be added

Episode 22: Skirmish In Skaro
To be added

Time of the Cybermen
To be added

Surf & Turf
To be added

Enlisted
To be added

Purity of the Daleks
To be added

Reverse the Polarity
To be added

Exodus of the Silurian
To be added

Proud Son of Sontar
To be added

Characters

 * The Doctor
 * Third Doctor
 * Fourth Doctor
 * Tenth Doctor
 * Twelfth Doctor
 * Thirteenth Doctor
 * Yasmin Khan
 * Sil
 * K9 Mark IV
 * Sarah Jane Smith
 * Bill Potts
 * John Benton
 * Clara Oswald
 * Martha Jones
 * K9 Mark I
 * Jo Grant
 * River Song
 * Ashildr
 * Liz Shaw
 * Sea Devil
 * Rose Tyler
 * Nardole
 * Leela
 * Vastra
 * Tala
 * Rory Williams
 * Dan Lewis
 * Strax
 * Jenny Flint
 * Kate Stewart
 * Petronella Osgood
 * Missy
 * Kerb!am Man
 * Eldane

Items

 * Waypoints
 * Cards
 * Waypoint Cards
 * Character Cards
 * Item Cards
 * Kerblam Boxes
 * Free Kerblam
 * Bronze Kerblam
 * Silver Kerblam
 * Gold Kerblam
 * Platinum Kerblam
 * Kyfred Gems
 * Henoch Matter
 * Mondasian Ingot
 * Ancient Eggs
 * Classified Dossiers
 * Cellular Matrices
 * Silurian Warrior Masks
 * Ammo Packs

Locations

 * Main locations
 * Castle-gate ruins
 * Cyber-ship
 * Victorian London beach
 * UNIT HQ, London
 * Dalek City, Skaro
 * South Pole, Antarctica
 * Court, Silurian city
 * Sontaran Time Ship
 * Waypoints
 * UNIT Lab, London
 * Dalek City, Skaro
 * Diner TARDIS
 * Atlantis, Earth
 * Minyan Ship R1C
 * Victorian London
 * Panopticon, Gallifrey
 * Pandorica, Underhenge
 * Mars
 * UNIT Moonbase, The Moon
 * Christmas Town, Trenzalore
 * Snowcap Base, South Pole, Antarctica

Crew
to be added

Story notes

 * This story is one of few to explictly suggest that Clara Oswald was able to remember her splinters' lives: the main Clara states that her memories of crossing the Doctor's time stream are "a bit blurry now", but is still able to refer back to her experience as Oswin Oswald, using her inside knowledge of Dalek psychology to thwart another Dalek.
 * Episode 8, which features a Sea Devil, is entitled A Deep One. The Deep Ones are antediluvian, fish- or batrachian-like sea-dwelling humanoids from the works of H. P. Lovecraft. All-Consuming Fire previously implied that Lovecraft's Deep Ones and the Sea Devils were one and the same.

Continuity

 * The UNIT HQ building of the Third Doctor's era has recently "passed through the event horizon of a black hole". (TV: The Three Doctors) The Third Doctor saved the World Peace Conference "last January". (TV: The Mind of Evil)
 * The Tenth Doctor recalls to Sarah Jane Smith how he and her previously visited an even earlier version of Skaro. (TV: Genesis of the Daleks) Sarah reminds the Doctor that he also once told her about his very first encounter with the Daleks, when "they all lived in a city and ran on static electricity". (TV: The Daleks)
 * The Twelfth Doctor repeats the Eleventh Doctor's claim that he only "borrowed" the TARDIS and "always planned" on bringing it back eventually. (TV: The Big Bang)
 * Due to the temporal disturbances, the Twelfth Doctor meets a post-Trap Street Clara again in the very Nevada desert where they last parted ways. He remembers Clara and her death, but not this place. (TV: Hell Bent)
 * The younger Clara is wearing the outfit she did during her adventures on Skaro. (TV: The Magician's Apprentice, The Witch's Familiar)
 * Clara recalls how she was a Dalek for some time, and knows what it's like to be a "confused" one, but subsequently "got better". (TV: Asylum of the Daleks)
 * The Crystal of Kronos is visible in Atlantis. (TV: The Time Monster)
 * Martha Jones is pulled off-course by the disturbances while she's travelling using Project Indigo trying to activate the Osterhagen Project. She stays only briefly and departs again while holding on to the thought "there's no place like home". (TV: Journey's End)
 * The Fourth Doctor claims to have "some experience" with vortex manipulators due to an adventure "a few years back near Auderly House" which involved "Time Guerillas from the 22nd century". (TV: Day of the Daleks)
 * The Twelfth Doctor remembers his previous visit to the Underhenge and the nature of the Pandorica. It is still guarded by two Cybermen who believe that the Doctor must be incapacitated to "save the universe". (TV: The Pandorica Opens)
 * The Third Doctor has promised Jo Grant that he will take her to Metebelis III to see the blue crystals, but she has a feeling that they'll get side-tracked and end up someplace else. Indeed, when the Doctor eventually reached Metebelis, it spelled his death and regeneration. (TV: Planet of the Spiders)
 * River Song is aware that her real first meeting with the Tenth Doctor is at a later point in his timeline, when he is travelling with "the ginger girl". To preserve the timeline, she slaps a memory worm on the Doctor while he's distracted, erasing his memory of the encounter. (TV: Silence in the Library)
 * Rose Tyler is wearing the outfit she wore during her involvement in the 21st century Dalek invasion, and mentions that she's faced the Daleks "three times with two Doctors". (TV: The Parting of the Ways, Doomsday, The Stolen Earth)
 * Benton relates to Jo how Cybermen attempted to invade Earth "five years ago", and were defeated by UNIT "with the Doctor's help". (TV: The Invasion)
 * Bill mentions that Nardole is meant to be guarding the Vault. (TV: The Pilot, etc.)
 * Early in the Time War, the Daleks wiped our multiple species to prevent them from allying with the Time Lords in the War. (AUDIO: Desperate Measures)
 * The Fourth Doctor and Leela return to the P7E a short time after their first adventure there, both from their own perspective and the Minyans'. (TV: Underworld)
 * The Doctor tells Vastra that there's a dinosaur loose in London "again", and Vastra initially assumes he brought it there using the TARDIS again. (TV: Deep Breath)
 * The Doctor recalls that "the Silurians at Wenley Moor" used high-frequency devices to control their dinosauroid "attack animals". The Silurians also threaten to use the Silurian plague again. (TV: Doctor Who and the Silurians)
 * The three Silurians form a Triad. (TV: Warriors of the Deep)
 * Vastra relates that there was "an accident" that left her the only survivor of the Silurian groups. (TV: A Good Man Goes to War)
 * Symbiotic nuclei, the part of a Time Lord's genetic code which makes them time-sensitive, are featured. (TV: The Two Doctors)
 * The Doctor tells Vastra about facing the Fisher King before being interrupted. (TV: Before the Flood)
 * A note written by the Master quotes the Doctor as having said "if we fight like animals, we die like animals" in Logopolis. (TV: Logopolis, Survival)