Dear BBC executives: if you want to have a surprise twist, don't reveal it in the trailer.
Seriously. My first note on Dark Water, after seeing the cybermen in the big image on BBC iPlayer, was "ugh I hate the cybermen, I don't know if I'll enjoy this." Which is generally true, but not something I want to go into an episode thinking, when the cybermen don't show up until almost the end. I was slow enough not to realize that "water that only shows organic matter" must be hiding the cybermen almost until the show revealed it itself, but I'm sure other viewers figured it out early on, ruining what was otherwise a gradual development of awesome. I think this incarnation of the cybermen has the potential to be really compelling and emotional, but that relies, in part, on thinking of them as dead friends and relatives, and not as "the cybermen" -- something that needs the episode's gradual build-up, rather than the "omg the cybermen" trailer reveal.
Luckily, the episode had enough other twists to make up for it. Like Danny's death. And the reveal that Missy is the Master. And the fact that Steven Moffat managed to write poignant lines and consistent character emotion.
Despite the Doctor's obligatory "darkest hour" speech, this episode wasn't part of the finale one-up-man-ship, where they have to save the world, then the universe, then all of existence, then all that ever was or ever will be, then the very concept of time itself, then... I don't even know where you could escalate to then. The show seems to have realized that you can't keep escalating the stakes forever, and that instead of a melodramatic "we've never faced anything like this" speech, identical to the speech from the last time they faced something like this, maybe the stakes could be smaller and personal. Not "all of time will end" but "Clara's boyfriend is dead."
Sure, now we have the Master (or the Mistress), and a massive cyberman army, and probably a threat to all of humanity, but it had a slow build, it had its foundations in character and emotion, and it made sense. There were no leaps of logic, no time loops, no jumping around in the TARDIS and revelations out of nowhere. My biggest question was why Clara had post-it notes all over her shelves at the beginning of the episode, and why she was speaking like she was about to die. Which, in the grand scheme of "I don't quite follow"s, is pretty minor.
Unfortunately, inconsistent character arcs from before this episode marred this one a bit. Clara's dramatic attempt to force the Doctor to save Danny's life was compelling, but it would have been more compelling if the show had been consistent with her "the Doctor can't be trusted and I don't want to travel with him" storyline. The moment could have packed a much greater punch if she really hadn't travelled with the Doctor since she told him she never wanted to see him again, and called him up just so she could force him to save Danny's life. Her ruthless decision making, and the Doctor's reaction to that, would have carried much more weight at the end of a consistent season-long arc of disappointment and betrayal. As things were, I found myself thinking that Clara's scheme was simply poorly thought out -- as he proved, she could have just asked before resorting to trapping them both in a volcano for all eternity.
I also think the "Danny dies" twist would have had more impact if his relationship with Clara wasn't so frustrating and unhealthy, but that's a discussion for a post of its own.
And then there's the fact that Missy is the Master. As far as I can remember, this is the first time a woman has played a timelord in the new series. And not just any timelord, but the most iconic one we've ever seen, after the Doctor himself. So we have canon proof that a major timelord character can change gender, and that feels important considering all the past conversation about the possibility of a female Doctor.
Either that, or it's a bone thrown to everyone who ever said, "hey, maybe the Doctor could be anyone other than a white man for once?"
I'm sure that parts of Doctor Who fandom are tearing themselves apart over this revelation, but to be honest, it didn't feel like that big a deal to me while watching the show itself. It was more "gasp, the Master is back" than "gasp, the Master is now a woman," and I think that sort of natural development is really important. The fact that the Master is a woman shouldn't be the key point within the show, even if it's all anyone talks about outside of it -- it should be that the Master is here, plotting evil again. And I think the show pulled that off.
A couple of points have been bugging me, though. First, the name. The whole Missy -> Mistress -> Master thing was necessary to hide the big reveal, but I'll be intrigued to see how she's addressed next week. If everyone starts referring to her as The Master, then we'll again see the show treating this as a perfectly natural change, and insisting that the two incarnations are ultimately the same character. If she remains Missy, however, there'll be a clear line separating her from all previous incarnations, which will be far more troubling.
The second thing that bugged me was Missy/the Master's attitude to the Doctor. She kissed him, called him her boyfriend, and generally emphasized the idea of a relationship between them -- something that remained far more sub-text-y when John Simms played the Master. Is this a case of the show finally feeling that it can explore this stuff now that the Master is a woman? Or of the show seeming to think that every female character must be in love with the Doctor? Again, we'll have to see where it goes next week, but it's another point that sets off potential alarm bells.
Because, off course, even this well-thought-out and twist-packed episode couldn't avoid the show's little sexist tics. The Doctor still had to say Clara was "whining" for being upset over her boyfriend's death. He still had to insult her looks, by saying that her sadness "put years on her face, and what if people see us together?", by telling his grieving friend that it "looks like you've been melted," for no reason whatsoever, except to show how humorously unattracted he is to Clara. Every. Single. Episode. And now the Master is a woman and calls him her boyfriend, and Clara is desperately in love with a man she felt she had to lie to about her life, and why why why? This season has done so many great, fun, compelling things. It's had so much more diversity, it put so much more thought into its secondary characters, it has improved so much over the mess of the previous seasons. So why does it have to do these things as well?
That said, I really can't wait for next week.