Picking up from the previous week's cliffhanger - Missy is the Master! The dead are being resurrected as Cybermen! Clara is about to be "deleted" by a trio of Cybermen! - Season 8 wraps up not only the story line started in "Dark Water" but also puts the finishing touches on several season-long themes. Well, mostly. But I'm getting ahead of myself.
I've watched the episode twice now, and I still am not sure how much I like it. Some parts are very good indeed, some parts wrap up story lines in a satisfying way, while other parts are... not my cup of tea.
Long Spoiler-Filled Plot Recap Section
Outside St. Paul's, Osgood (from UNIT) and Kate Lethbridge-Stewart arrive with a number of UNIT soldiers, ready to take on the Cybermen, who evade UNIT by flying away, Iron Man-style. The roof of St. Paul's opens and more Cybermen leave, ready to "pollinate" the world with nano-particles that will create new Cybermen out of dead bodies plus the consciousness, now stored in the Nethersphere, of those bodies. UNIT sedates Missy and, oddly, the Doctor. The two are taken aboard a plane - Missy as a prisoner and the Doctor, now conscious, as President of Earth in order to deal with the Cybermen threat.
In the Nethersphere, with Danny, Seb, and the young Afghan boy Danny killed, Seb explains that they will be returning to their bodies - with a bit of an "upgrade." On Earth, the nanoparticle "rain" falls on a graveyard and in a funeral home, where Danny's body lies. Back in St. Paul's, a rogue Cyberman - Danny - arrives. Clara, not knowing his identity and still trying to save her life, says, "I'm an incredible liar. Ask anyone." Cyber-Danny replies, "Correct," then blasts the other Cybermen and knocks her out.
Missy claims she knows Gallifrey's location. Missy kills Osgood and flying Cybermen bring down the plane. Kate is blown out of the plane's cargo door. As the plane explodes, the Doctor falls, inserting the TARDIS key into the falling TARDIS - cue the James Bond music.
Clara comes to in a cemetery (why?) with Cybermen breaking out of the ground but not attacking anyone. She tells her rescuer that the Doctor is her best friend, the one persokn she'd never lie to - at which point Cyber-Danny removes his faceplate, revealing his identity to her.
Clara calls the Doctor on the TARDIS telephone - Danny wants his emotions removed, but can't activate the emotional inhibitor on his chest by himself. The Doctor implores her not to do it, as Danny will then be a full Cyberman and kill Clara. The Doctor arrives and wants to know Missy's plan, but Cyber-Danny can't tap into the hive mind without activating his emotional inhibitor. Clara zaps it with the sonic screwdriver. As Danny promised, he is able to resist Cyber control and doesn't attack Clara.
Missy arrives a la Mary Poppins, floating from the sky with an opened umbrella. She gives the Doctor her "gift" - control of the Cybermen, "an indestructible army to rage across the universe." She observes, "Give a good man firepower and he'll never run out of people to kill." She tells him, "I need you to know we're not so different. I need my friend back." Although he considers her offer, as he believes he needs the Cybermen to burn away the nanoparticle storm, he ultimately rejects it, telling Missy, "I am not a good man. I am not a bad man... I'm an idiot with a box."
The Doctor gives the control device to Cyber-Danny - who tells the newly-converted Cybermen now under his command that "Today is not a good day," but that as soldiers their promise to civilians is that they will sleep safely tonight. The Cybermen fly to the nanoparticle cloud and self-destruct, destroying the particles.
Missy tells the Doctor the coordinates of Gallifrey, assuring him that she's not lying this time.
Clara tries to kill Missy, but the Doctor, concerned what Clara will become if she resorts to cold-blooded murder, says he'll do it himself if that's what it will take to save Clara. Instead, Missy is zapped by a Cyberman, who then indicates to the Doctor and Clara the still-alive Kate. The Cyberman is clearly the late Brigadier Lethbridge-Stewart - hey, if you can't save your own kid, what's the point of being a Cyberman? - and acknowledges the Doctor's salute before flying off.
Danny, somehow back in the Nethersphere (we presume - though it's not clear how this happened), has found a way to send one person back to the land of the living. Clara expects him, but instead he sends the Afghan child, telling Clara to find his parents - this was a promise he had to keep.
The Doctor takes the TARDIS to the coordinates Missy gave him, but finds no Gallifrey - she lied again. In a rage, he whomps the TARDIS console.
Clara and the Doctor meet, and the Doctor believes Danny sent himself back to Earth. She lies and agrees with him, saying that the two are together, and he lies that he found Gallifrey, and that this is it for them. She asks him to hug, and he relents. She asks him why he doesn't like hugs, to which he replies, "Never trust a hug. It's just a way to hide your face" - as both look devastated.
The credits roll, but are interrupted by Santa's arrival at the TARDIS. Santa says, "It can't end like this," leading to a guess that clara's story will continue in the Christmas episode.
It's All About Control
At the same time, the ongoing tug-of-war between Danny and the Doctor also reflects the question of control. Danny, the soldier, views the Doctor as an officer, one of those responsible for getting ordinary soldiers into predicaments without fully understanding the costs of doing so. The Doctor, always one to enjoy being in control of situations, found himself having to or choosing to relinquish control multiple times during the season. In "Flatline," he was unable to leave the TARDIS for most of the episode, and had to rely on Clara, while in "Kill the Moon" he chose to leave at a crucial time, insisting that the three humans had to make the decision whether to kill the creature about to hatch.
Control plays a big role in "Death in Heaven" as well. Missy's scheme involves creating an army of Cybermen capable of dominating any planet, and then gives control over this army to the Doctor in an effort to... well, what, exactly? By taking control of the Cybermen, the Doctor would be acknowledging that he and Missy are not so different. While the Master's schemes involve using power for his own Machavelian ends, the Doctor also uses other people to further his plans. Although those plans involve saving people and generally trying to do right, at some level the difference between the Doctor and Missy is more one of judgment than anything fundamental. When the Doctor gives up the device that controls the Cybermen, he's rejecting Missy's equating the two of them. He even thanks her, saying he's not a good man, not a bad man, just an idiot with a box who tries to do the right thing. (Of course, turning the Cybermen over to Danny, who then uses this force to save the planet only at the cost of destroying all the Cybermen, including himself, might suggest that both Danny and Missy were correct: the "officer" used his soldiers as cannon fodder once again.)
A few other examples: Danny tells Clara he wants to activate his emotional inhibitor, but can't do it himself, giving her control over him. At the very end of the episode, when he can send one person back through the Nethersphere - sadly, with no explanation of why that might be possible, save that earlier we apparently saw Missy travel to and from the Nethersphere - he chooses to send the Afghani boy he killed, rather than resurrecting himself, a last act of self-sacrifice that re-establishes his control over his destiny.
Should We Care More About Zany Plots or Emotional Resonance?
But the enjoyment of Doctor Who isn't about rigorous plots any more than it was about special effects back in the days of the classic series. It's about stories, and emotions, and relationships, and the success of an episode, or of a story arc, depends on how deftly writers draw the characters, how the actors bring those characters to life, and how the audience reacts emotionally to the character interplay and development. By those standards, the season finale was a success. I'm not convinced that making Missy the Master was necessary or wise; I think I would have preferred that Missy be a new character, even if her plot was the same. Still, Michelle Gomez made a wonderful and, yes, bananas Master.
One thing I thought worked superbly was the ending. As Erika Ensign of the Verity! podcast remarked, throughout the season Clara lies for her own benefit: to keep Danny from knowing about her adventures with the Doctor, to keep the Doctor from know she's lied to Danny, to keep the Cybermen from killing her, and so on. Yet in the end, in the scene in the restaurant, both Clara and the Doctor lie to one another out of selflessness.