Under the Lake (TV story)

 was the third episode of the ninth series of Doctor Who produced by BBC Wales.

It saw the series revisit the concept of ghosts and hauntings, last explored in the television story Hide. The episode poses another explanation for the apparitions, in this case as resurrected transmitters of an alien presence's signal.

It also continued the thematic concept of the Doctor apparently facing death, with the end of the episode setting up yet another opportunity for the Doctor to reflect on his mortality.

Synopsis
Arriving on an underwater base under attack, it's up to the Doctor and Clara to save the frightened crew. But also onboard is an alien spaceship, and the base is being haunted by the most impossible of things.

The Doctor's deepest beliefs are challenged when he encounters something he cannot explain. Can it really be possible? Can ghosts be real?

Plot
In an underwater mining facility based in Scotland, 2119 designated The Drum, the captain, Moran, is recording a log in his journal. Moran states that the team has discovered a small craft located on the bank, and, as they are unable to analyse it from within the base, they have brought it inside, where he and the crew will investigate.

A crew member named Lunn interprets the sign language of another crew member, Cass, saying that the reason for its sudden appearance is due to underwater movement and shifts on the floor of the lake. Another crew member named Pritchard recommends they discuss ownership the spaceship, prompting Moran to tell everybody to stop calling it a spaceship, as they don't know what it is; he thinks it may be an experimental craft left behind by the government. However, he is meet with annoyance as this thing is beyond any human technology.

The crew enter, and Moran notices something inside the craft, asking Lunn to hand him a torch. Lunn does so, but glimpses a ghostly figure reflected in the glass. He reluctantly hands Moran the torch. Moran investigates four strange markings on the wall, whilst Lunn asks Cass why he shouldn't go inside. Whilst they bicker, Pritchard cries out as he glimpses the ghost, accidentally starting the engines. Moran pushes Cass out of the way of the boosters' range, but is struck by the blast, forcing the crew to retreat, leaving him behind.

O'Donnell, another crew member, bangs on the sealed door, demanding they go back for Moran, but is told it is impossible by the rest of the crew. She yells at Pritchard for messing with the controls, but is interrupted as Cass screams. She turns, startled to see a ghostly Moran, with gaping back holes for eyes hovering in front of her. The same figure appears, and the pair reach out to the crew...

3 days later, the facility is a wreck, being seemingly empty. The TARDIS appears, with Clara, and the Doctor stepping out, with him realizing that they are in the 22nd century. Clara laughs, asking if they can go back to the planet where people with long neck have been celebrating New Years for 2 centuries, as she left her sunglasses behind. Taking notice of the surroundings, and their abundance of fun places, Clara suggests that the Doctor is just itching to save a planet; she can't wait to have another adventure.

The Doctor and Clara explore, with them wondering where the crew is; they find the mess hall well... a mess. Furniture scattered everyone and food half-eaten, with cutlery stabbed into the walls. "Wish granted" the Doctor sourly tells Clara. She wonders if they've arrived too late to help. The Doctor sticks his finger in a mug of coffee, noting that it was hot 8 hours ago, meaning there might be survivors who can tell them about what happened.

They continue down a corridor, where they spot the ghosts kneeling. The Doctor calls out to them, and the two ghosts approach them; Clara is scared, while the Doctor thinks they're just curious. The ghosts leave, with the Doctor and Clara following. They enter the hanger, where Clara wonders if the vessel if a submarine; however, the Doctor confirms that it's an alien spaceship. They go inside, finding it in the same condition as before Moran's death. The Doctor notices the strange writing and directs Clara's attention to it; he grimly tells her that the TARDIS can't translate the writing, which is bad news. Clara then notices that the ghosts have returned. The Doctor asks if they wanted them to see the writing. To their shock, the ghosts grab a harpoon gun and spear. The Doctor wonders if it's something Clara said, as she even got in a fight with Gandhi. The ghosts attack, prompting the Doctor and Clara to flee. The ghosts follow through the walls, but are forced to leave their weapons behind. The duo run through the halls until they find O'Donnell urging them to come into a room. The Doctor and Clara rush in and the door is shut behind them. The crew demand to know who the two are, prompting the Doctor to introduce himself and brandish the psychic paper. Pritchard is shocked to learn the Doctor's from UNIT; it's a first for the psychic paper to show something that isn't a lie. To the Doctor's surprise, O'Donnell shakes his hand and tells him it's an honor to meet one of him. The Doctor wonders why they are safe here, to which the answer is the ghosts cannot come into the Faraday cage for some reason. However, the Doctor tells them there is no such thing as ghosts.

The Doctor demands to know who's in charge, so he can know who to ignore. Pritchard claims he's in charge, but Lunn tells him that Cass is technically in charge; he starts translating for Cass, but the Doctor tells him that he can understand sign language. However, after Cass starts, the Doctor admits he can't understand; he guesses it got deleted from the TARDIS for Semaphore. Cass explains that the trouble started when they brought the ship onboard; Moran died, and then he and the mole fellow started trying to kill them. The Doctor notes the oddity of the other ghost, as it's a Tivolian; it's species is known for beings cowards. A computer voice tells the crew that day mode has been activated, prompting a sigh of relief. The Doctor asks about the things that tried killing them, to which O'Donnell explains they only come out at night; "Funny how that doesn't make me feel better." Clara retorts.

Back in the hanger, the Doctor decides to examine the ship to understand the presence of the ghosts. He asks why the crew didn't abandon the base and leave the ghosts down there alone. Pritchard explains that it was his call; Vector Petroleum could not afford to lose the mining equipment. Patting his shoulder, the Doctor states: "I completely understand; you're an idiot." The Doctor goes back into the ship, while Lunn and Cass argue; he asks what the problem is. Lunn states Cass is telling him it's too dangerous to go into the ship. The Doctor goes back to examining the ship, stating that there are parts of it missing, such as the stasis pod for the pilot and one of the power cells. Pritchard takes notice of the power cell, asking how powerful they are; according to the Doctor, powerful enough to "zap" from one side of the universe to the other. The Doctor goes over everything they've learned, coming to the conclusion that they ARE dealing with ghosts. In the control room, Clara tells the Doctor that he scoffed at the idea of ghosst, to which he says that there used to be no such things as smart phone, socks and badgers; then there were. Overjoyed, the Doctor asks why no-one is interested in trying to ask the ghosts what their state of existence is like. He is meet with glares. Bennett tells him that Moran was their friend. Clara whispers to use "the cards"; seeing she's right, the Doctor turns his back and pulls out a stack of cue cards. He rummages through them to find the right one. Clara takes the cards and pulls out the one he needs; he reads it, stating he will do all he can to solve/avenge the death of their loved one.

Suddenly, the base announces that night mode has been activated; this doesn't make sense as it's too soon. Everyone panics, getting ready to head back to Faraday cage. O'Donnell calls for Pritchard over the intercom, telling him to go back to the Faraday cage. However, it turns out he has just gotten back inside from searching for the other power cell. Seeing a figure outside the decompression chamber, he assumes it's Bennett and says he should try getting the ship labeled an asset. When he sees it's Moran's ghost, he yells in fear; Moran opens the exit, letting in water. Clara and Lunn find Pritchard in the mess hall, and then look out the window to see a body floating. They yell a man over board, but soon see it's Pritchard. The ghost attempts to go after them, but thanks to O'Donnell's quick thinking, the base is put back into day mode and the ghosts vanish.

Seeing the footage of Pritchard's drowning, the Doctor comes to the conclusion that the ghosts are getting smarter; since they cannot come out in day mode, they've been working to change the base's systems into death traps. Cass decides to call Topside to get eveyone out, since she will not tolerate another member of her crew being killed. However, when O'Donnell contacts Topside, it turns out a medic sub has been sent, via a morse code. The Doctor takes over the call, using his UNIT security visa to authorize his command; he tells them there's an unknown contagion and must be quarantined. The sub is pulled back. Bennett wonders why, to which the Doctor explains; the ghosts sent the message. "And I'm pretty sure it's not so they can form a boy-band." The reason they keep dying is because they don't know what the ghosts want. They need to capture the ghosts.

On the Doctor's order, O'Donnell puts the base back into night mode to reactivate the ghosts. In a relay race of sorts, Bennet, Clara and Lunn will lure the ghosts to the Faraday cage. However, the plan hits a snag; Lunn isn't interesting to the ghosts.

To be continued...

Cast

 * The Doctor - Peter Capaldi
 * Clara - Jenna Coleman
 * Moran - Colin McFarlane
 * Cass - Sophie Stone
 * Lunn - Zaqi Ismail
 * O'Donnell - Morven Christie
 * Bennett - Arsher Ali
 * Pritchard - Steven Robertson
 * Prentis - Paul Kaye

Astronomy

 * The ghosts refer to Orion's sword.
 * The Orion Nebula, Orion, Rigel and Betelgeuse are mentioned on a map of constellations.

The Doctor

 * The Doctor uses cue cards to give apologies.
 * The Doctor once converted his radio into a clockwork squirrel.

Technology

 * The base has a Faraday cage which, when locked, the ghosts cannot enter or exit.
 * The Doctor refers to holograms.
 * The sonic sunglasses can connect to Wi-Fi.
 * A suspended animation chamber is found under the water.
 * The Drum has a submarine that can be controlled with submarine manipulator rings.
 * The Doctor refers to the fact that there were no such thing as socks, smartphones or badgers, until they came into being.
 * A submarine is contacted via Morse code.

Organisations

 * The Ministry of Defence and the British Army are mentioned, and stated to have had a facility where the spaceship found.
 * Vector Petroleum is the company in charge of the Drum.
 * UNIT is still operational.
 * The Doctor states that his UNIT security visa is 7-1-0-Apple-0-0, which is enough for him to be recognised despite it being more than a century into the future from when he is normally associated with UNIT.
 * The Drum crew refer to their colleagues above the surface as "Topside."
 * Drum Control is where the rest of the base is controlled.

Individuals

 * The Doctor states that he has met Shirley Bassey.
 * The Doctor states that Clara once had an argument with Gandhi.
 * Clara refers to people with long necks who have been celebrating New Year for two centuries.
 * Cass is the most intelligent of the remaining crew.

Food and beverages

 * A cup of coffee is seen on a table; the Doctor is able to work out how long it's been there by tasting it.
 * Clara states that the Doctor raved about ghosts "like a kid who has had too much sherbet."

Languages

 * The Doctor can no longer understand British Sign Language. He believes it has been deleted from the TARDIS language bank, along with semaphore. Despite this, he nonetheless correctly signs "you're beautiful" to Cass when he attempts to communicate with her and partially, and apparently unconsciously, partially signs the American Sign Language sign for "I love you" when speaking to Clara in the TARDIS about his "duty of care".

Popular culture

 * The Doctor states that he once had Peter Andre's song "Mysterious Girl" stuck in his head for two weeks, and that it drove him mad.
 * Cass refers to the Doctor doing "the Cabin in the Woods" thing.

Story notes

 * The Radio Times programme listing was accompanied by a small colour head-and-shoulders shot of Morven Christie as O'Donnell, with the accompanying caption "Doctor Who / 8.25 p.m. / Could O'Donnell and her colleagues have fallen victim to undead beings?"
 * The working title of the story (and the following episode) was Ghost in the Machine. (DWM 492)
 * This was the first episode since The Unicorn and the Wasp not to feature the sonic screwdriver.

Ratings

 * BBC One overnight: 3.74 million
 * BBC America overnight: to be added
 * UK final ratings: 5.63 million

Production errors

 * Recordings of Prichard's drowning portray his words and movement slightly differently.
 * When Clara and the Doctor run from the "ghosts" and are directed to run towards the Faraday cage (down a straight corridor), Jenna Coleman ducks below the camera.

Continuity

 * The Doctor uses his sonic sunglasses. (TV: The Witch's Familiar)
 * One of the ghosts was previously a Tivolian. (TV: The God Complex)
 * The Doctor has previously landed in an underwater base, in which he met with a crew that were tackling a threat that would re-animate the dead crew. (GAME: Shadows of the Vashta Nerada)
 * The Doctor uses his psychic paper as proof of ID. (TV: The End of the World et al)
 * The psychic paper tells the crew that the Doctor works for UNIT. (TV: Spearhead from Space et al)
 * One of the Doctor's apology cue cards says: "It was my fault, I should have known you didn't live in Aberdeen". The Fourth Doctor dropped Sarah Jane Smith off there rather than in South Croydon. (TV: The Hand of Fear, School Reunion)
 * Another of the cue cards says: "No one is going to be eaten / vapourised / exterminated / upgraded / possessed / mortally wounded / turned to jelly. We'll all get out of this unharmed." "Exterminated" is a reference to the Daleks, (TV: The Daleks et.al.) "upgraded" is a reference to the Cybermen, (TV: Rise of the Cybermen et.al.) and "possessed" is a reference to various races and beings. (TV: The Impossible Planet/The Satan Pit et al)
 * When the Doctor goes back on his insistence that the phantoms of the dead aren't ghosts, he notes that they aren't flesh avatars, (TV: The Rebel Flesh/The Almost People) Autons, (TV: Spearhead from Space et.al.) or "digital copies bouncing around the Nethersphere". (TV: Dark Water/Death in Heaven)
 * The Cloister Bell alerts the Doctor to a threat to the TARDIS. (TV: Logopolis, Resurrection of the Daleks et al)
 * The Doctor indirectly refers to Danny Pink (TV: Into the Dalek, et al) when suggesting Clara begin a new relationship.
 * Clara has previously stated that she doesn't believe in ghosts (TV: The Snowmen), and she and the Eleventh Doctor once investigated another "haunting" that turned out to be non-ghost in nature (TV: Hide).
 * Clara tries to "high-five" the Doctor. (TV: Hide)

DVD releases
Under the Lake was released on DVD as part of "Doctor Who: Series 9, Part 1" on November 2 in region 2 and November 3 in region 1.

Blu-ray releases
Under the Lake was released on Blu-ray as part of "Doctor Who: Series 9, Part 1" on November 2 in region 2 and November 3 in region 1.