Inspirations: Dark Water / Death in Heaven

Dark Water / Death in Heaven formed the two-part finale to Peter Capaldi's first season, and reintroduced the Master in a new incarnation.

Interestingly, RTD had first retooled the Daleks when he took over, then the Cybermen and then the Master over the course of time - and now Moffat has done the same during his few series in charge: the New Paradigm Daleks in Series 5, the "Iron Man" Cybermen in Series 7, and now a female Master in Series 8.

Those new Cybermen also appear in this. This makes it the fifth time they've turned up in the penultimate episode of a series.

The episode begins with a bit of a shock as semi-regular Danny Pink is killed in a road traffic accident. Clara wants the Doctor to intervene and save him - something which takes us right back to the origins of the series. In The Aztecs, the Doctor tells Barbara that they cannot change history - "not one line!". He doesn't elaborate on why this should be, but does state "believe me, I know" - suggesting he has tried and failed to change something himself, or it is something which was explained to him back on his home planet. There appears to be some sort of law, but whether it is natural or manufactured and imposed isn't explained.

When we get to The Reign of Terror just a couple of months later, we learn that it does indeed seem to be some natural force - as though "Time" itself can intervene. There's talk of how trying to shoot Napoleon would inevitably see every attempt fail. This, of course, contradicts The Aztecs, where the Doctor fears that Barbara really could alter history.

When it comes to the deaths of Katarina and Sara Kingdom, the idea of using the TARDIS to somehow save them isn't even considered.

The next companion death isn't until Adric's in Earthshock and here the Doctor specifically states that he cannot (or will not) change what has happened. (Might just be he's glad to see the back of him, mind you...). Tegan and Nyssa ask him to intervene, and he angrily tells them never to ask him to do anything like that again.

The "deaths" of Amy and Rory are different. Here they have gone back in time and died natural deaths, and there's some business about the TARDIS being unable to visit New York due to all the temporal paradoxes. (What was to stop the Doctor simply landing somewhere else that year and fetching them back by train, car, steamship etc is never explained).

In this story, Clara tries blackmailing the Doctor into changing Danny's fate, and he refuses - though only to see how far she will go to force him. He doesn't try using the TARDIS to go back and stop Danny being run over, however. Instead he decides to use Clara's link to the telepathic circuits to bring the ship to where he now is, which he believes is the Afterlife. 

Which is a long-winded way of getting us to the first big inspiration on show - the myth of Orpheus in the Underworld. Greek myths had formed the basis of Doctor Who stories in the past - especially if Anthony Read was involved. He had script-edited Underworld and written The Horns of Nimon. A Gorgon had also featured in The Mind Robber, as had a Minotaur - creatures which have popped up a few times in the series over the years.

Musician Orpheus is wed to Eurydice, a wood nymph, and one day she is bitten by a viper and dies. He uses his skills to charm Cerberus to get into the Underworld to find her and bring her back. Hades allows this - on the condition that he does not look back but trusts her to follow him. He can't resist a peek just as they are about to leave the domain, and so he loses her forever.

Here, Clara fulfils the Orpheus role - going in search of her lost love. As with the Greek myth, they are reunited only for her to ultimately lose him - Danny electing to free another "soul" from the Afterlife in his place. This is a boy whom he inadvertently killed whilst on active service, and it has been hinted throughout the series that he was suffering from some form of PTSD relating to is time in the army.

It turns out that the Afterlife isn't any sort of spiritual domain, but an artificial one - Gallifreyan technology based on the Matrix (first introduced in The Deadly Assassin, in which the villain is also the Master in a new form). 

Many fans guessed the identity of the mysterious woman who had been turning up throughout the series. Moffat was originally going to call her Misty.

A potential deflection was naming the founder of the 3W institute Dr Skarosa (suggesting a Dalek connection)

Moffat claimed that he had always wanted to write a Cyberman story (the previous ones during his tenure having been written by Gareth Roberts and Neil Gaiman) as they were his favourite monsters.

The image of the Cybermen in their tanks derived from memories of them in their niches on Telos in The Tomb of the Cybermen. 

He wanted a big cinematic story, so a series finale was the obvious choice. He also recognised the fact that these tended to be weak in the second half following a great opener and so decided that the cliff-hanger should see the story go off in a new direction (even though this was often the reason for the failings in the past).

Michelle Gomez had been offered the role of Miss Delphox in Time Heist but had been unavailable, but expressed an interest should anything else come up. Moffat saw the opportunity of matching the Glaswegian Doctor with a Glaswegian Master too good to miss, but elected to do something different with his arch-enemy. He claimed to have struggled to write for a female Master, until Gomez was cast.

It had already been suggested in dialogue that Time Lords could change gender (e.g. the Corsair in The Doctor's Wife) so the Master became the Mistress, or Missy for short.

Doctor Who references abound. 

The main one is the nod to the classic story The Invasion, in which UNIT had battled the Cybermen, with iconic scenes filmed next to St Paul's Cathedral. Kate Stewart even produces a damaged Cyberman helmet from this story.

The institute's name - 3W - might just possibly be a nod to The Wheel in Space, another Cyberman story. The Wheel's call sign begins W3. No? Attentive viewers would have recognised 3W's overlapping big circle / small circle motif as a Cyberman's teardrop eye design. This was first introduced in The Wheel in Space.

We learn that Missy was the woman who gave Clara the Doctor's phone number way back in The Bells of St John.

Clara's birthday is given as 23rd November - the series anniversary.

She has post-it notes on her fridge with "Blinovitch" (which would have referred back to Kill The Moon as Courtney was originally going to be the future Mrs Blinovitch), "Psi", "Vastra", "Saibra", "Robin Hood" and "Dinosaur in London" - all references to Series 8 episodes.

She also has the Hyperspace Body Swap ticket - which had featured in the Doctor Who Prom in 2013.

Pretending to be the Doctor, Clara claims to have been married four times. This would be to River Song, Elizabeth I, Marylin Monroe, and to the grandmother of Susan. (Missy sings "Happy Birthday, Mr President" in the same manner in which Monroe sang to JFK).

The funeral parlour where Danny's body lies is called Chaplet's - as in the surname of the First Doctor's companion Dodo.

Missy gives the co-ordinates of Gallifrey as first stated in Pyramids of Mars (10-0-11-00 by 02, in the constellation of Kasterborous).

Other references include the Cyberman attack on the UNIT aircraft, which comes from the classic 1963 Twilight Zone episode "Nightmare at 20,000 Feet".

The Cybermen emerging from their graves was a direct nod to George Romero's Night of the Living Dead (1968).

Missy descends from the sky holding a parasol - as in Disney's Mary Poppins (1964), and her dress mirrors the magical nanny's.

Missy calls out "Bring out your dead" - which was the cry heard around the streets of London during the Plague of 1665.

Colonel Ahmed and Osgood discuss the similarity of the Valiant to Cloudbase, which featured in Gerry Anderson's Captain Scarlet and the Mysterons, and mention how this is sometimes confused with Thunderbirds.

Next time: The Thing meets Alien meets Miracle on 34th Street meets Santa Claus Conquers the Martians...