‘Dark’ is an appropriate word for this episode, as while visually speaking it is bright, tonally speaking it is quite grim, spending most of the time on that most darkest of subjects, death.
Danny is run over and killed by a car, with Clara desperate to do something to change it. When she next meets the Doctor she asks to go to a volcano. On the way there she drugs the Doctor and gets all seven of his TARDIS keys. He had previously told her that the only thing that can destroy the TARDIS keys is volcanic lava. Clara threatens to throw all the keys into the lava, locking the Doctor out of his TARDIS forever, unless he changes time to save Danny’s life. The Doctor tells Clara this is impossible, as if he did that it would create a paradox; he would never have saved Danny’s life if Clara hadn’t done this, and if Danny hadn’t died she wouldn’t have asked the Doctor in the first place. Clara ends up throwing all the keys into the volcano, and regrets it immediately. Luckily, this turns out to have been a dream the Doctor induced, to see what Clara was planning and what would happen if she went through with it. The Doctor then says he will try and help Clara get Danny back somehow, saying that he cares too much about Clara to let betrayal get in the way.
The Doctor and Clara try to find Danny, and the TARDIS takes them to “the afterlife”, a museum like building filled with skeletons in water tanks. Missy is there too, and claims to be merely a service droid. There is a scientist there, Doctor Chang, who explains some of the inventions in the building and the scientific research behind them. He says that white noise is actually the voices of the departed trying to communicate, and having isolated the voices they are begging not to be cremated. This he says is why this place was built, as the dead were seen to remain conscious after they died.
There is also the invention which is the title of the episode, dark water, a liquid which acts like an X-ray, for example if you put your hand in the liquid, people will be able to see the bones of your hand.
Meanwhile, Danny has woken up in “the afterlife”, and is met by Seb. The afterlife here is extremely bureaucratic, rather like the one in Being Human, and it is noted that it is referred to by many names, such as Heaven, the Underworld, the Promised Land or the Nethersphere. Danny is met briefly by a boy he killed when he was a solider, something which still haunts him. He then gets a telephone call from “the other side”, which is Clara. Danny doesn’t want Clara to have to die to join him there, and becomes even more upset. Seb gives Danny a delete pad, telling him it will help destroy his emotions.
There is a twist in the tale, as Missy was lying about being a droid, and begins draining the water from the tanks. As the water drains out, we see that the skeletons are in fact Cybermen! The water used was dark water, which hid them allowing people only to see the skeletons of the humans used to make the Cybermen. She is about to unleash them, but not before she callously kills Doctor Chang having no further use for him.
The Doctor has figured out that a machine used, the Matrix data slice, is Gallifreyan. Missy has been uploading the consciousness of the dead into the machine, which gives them the illusion of being in the Nethersphere. She is planning to upload the consciousness into the Cybermen. As she puts it “Upload the mind, upgrade the body”, and “Cybermen from cyberspace”. She’s taking it further than those uploaded onto the date slice and those Cybermen too, saying “All the graves on planet Earth are about to give birth” and they will have no trouble taking over the world as “The dead outnumber the living”.
The big twist and the big reveal in this episode though was Missy’s identity. She tells the Doctor that she has in fact told him already. Missy, which is short for Mistress, which is the female equivalent of Master. She is a new incarnation of The Master!
This episode was very intriguing, discussing the concept of life after death. It had some good scenes. The sight of the skeletons in water was an interesting visual, and I loved the twist with them essentially being X-rays of Cybermen. Michelle Gomez was fantastic, and she has good chemistry with Peter Capaldi’s Doctor. I liked the exchange between them, referencing a well known meta joke about the Daleks not being able to climb stairs. As for the revelation of Missy’s identity, there are some that do not like the idea of the Master changing gender. I have no problem with that, the new series at least has made several references to the possibility that Time Lord regeneration can change gender, such as in The Doctor’s Wife for example. I would be fine if the Doctor was played by a woman in the future. Though I think I might have preferred Missy to have been a completely new character than to turn out to be The Master. But still, Dark Water is a brilliant episode.