Doctor Who/Recap/S27/E11 Boom Town

What are you captain of? The innuendo squad?

—Mickey, to Jack.

The Doctor, Rose, and Jack pop back to 21st-century Cardiff, so that Rose can meet up with Mickey, the TARDIS can refuel from the Cardiff rift, and mischief can generally be gotten into. Also, Jack isn't getting any from Rose, nor from the Doctor, which annoys him and amuses everyone else. (But the Doctor merrily flirts with him, which annoys him even more.) Still, our three travellers have bonded together in a way that really irritates Mickey, who is getting a little sick of all the inside jokes and all the flirting with each other that the three of them can cook up.

Mickey's state of mind is understandable, but he's being a bit of a jerk about it—especially uncool since today, the usually dour Ninth Doctor is relaxed and grinning, and it's a beautiful sight to behold. But perhaps Mickey's not entirely at fault, because ultimately what really harshes the Doctor's mellow is the sight of Margaret the Slitheen (from "Aliens of London" / "World War Three") as the mayor of Cardiff.

Oh, and she's presiding over the final stages of Cardiff's new nuclear power plant, a project she's been shepherding since its inception and which could not possibly go wrong. With all the safeguards and design reviews the power plant has had, for it to get this far it'd have to have been designed to fail! And indeed it is, as Margaret plans to use the invitable explosion to propel her to anywhere in the universe that isn't Wales. Oh, and it's called "Bad Wolf". For the first time, the Doctor realizes that those words are following them.

The gang chase Margaret, capture her, and imprison her in the TARDIS to await transportation to her home planet, where she's been convicted in absentia and faces the death penalty. She talks the Doctor into taking her out to dinner (using a pair of Jack's Time Agent handcuffs to prevent escape), where she alternates between trying to guilt-trip him and kill him.

She reveals that she's developed human feelings (which is true), that she's been trained to kill all her life (which is true) and that she's now trying to better herself and live in peace forever (which is a filthy lie). The Doctor defeats her by making her stare into the living core of the TARDIS, which causes her to revent back to egg form. Problem solved!

Tropes

Actor Allusion; Nine says he'd make a very bad God - Eccleston played Simon Baxter, the Son of God in Russell T. Davies' The Second Coming.
Arc Words: The Nuclear Plant project is named "Blaidd Drwg", which means Bad Wolf in Welsh.
- This is the episode where the Doctor first notices the phrase "Bad Wolf" following him around.
- Margaret points out that the Doctor messes with people's lives so much, one of the reason he is always running is because he "daren't look back". Davros mocks the Tenth about this in "Journey's End" and the Dreamlord tells Amy this about the Eleventh in "Amy's Choice".
Becoming the Mask: Margaret has been in her human disguise for so long that she's starting to empathise with humans, particularly the Welsh.
Chekhov's Gun: The "pan-dimensional surfboard" will become one of the Doctor's most useful gadgets in the next few seasons. The Cardiff nuclear power plant eventually plays a major role in Torchwood, and in that same episode, the Time Agent handcuffs also make an appearance.
Cool Board: The extrapolator's intended purpose is a "pan-dimensional surfboard", which Margaret can use to ride the shockwave of an exploding planet back to "civilization". The Doctor takes the extrapolator once she's regressed to an egg, and generally uses it as a force-field generator for the TARDIS.
Debate and Switch
Deus Ex Machina: An interesting variant in that while it's clearly an out-of-the-blue version in this episode, its appearance here acts as justification for the one in the season finale.
Earthshattering Kaboom: Margaret's plan for escaping the Earth also means annihilating it.
Even Evil Has Loved Ones: Of course the whole Slitheen family is evil, Margaret included, but she makes it clear early on that she really grieves for them and that she didn't see them as evil...

Margaret: I had quite a sizeable family, once upon a time. Wonderful brothers. Oh, they were bold! But all of them are gone now. Maybe you're right. Maybe I'm cursed.

Killed Himself Shaving: The hilarious demise of anyone who might find out the Cardiff reactor is rigged to explode, culminating in:

Cathy Salt: And then just recently Mr. Cleaver, the government's nuclear advisor?
Margaret Blaine: Slipped on an icy patch.
Cathy Salt: He was decapitated!
Margaret Blaine: It was a very icy patch.

Going Native: Maragaret / Blon - even while planning to blow up the entire planet, she mentions that the London government wouldn't notice if South Wales fell into the sea. "Oh. I sound like a Welshman. God help me, I've gone native."
Hannibal Lecture: The Doctor gives one to Margaret, who responds with one of her own.
Have You Told Anyone Else?: Twice. Although the second time Margaret spares her.
- Also, it's implied by the conversation with the reporter that it happened a lot more in the past.
He Knows Too Much
Ignored Epiphany: The Doctor, when the series' Arc Words finally come to his attention.
It's All About Me
Karma Houdini: Blon, dispite her attempt to destroy the earth to escape she still manage to get a good ending when she looks into the Heart of the TARDIS and becomes an Egg again, thus giving her what she wanted all along. A second chance.
No, Mr. Bond, I Expect You to Dine: a variant, with the villain in what's usually Bond's position.
Noodle Incident: Jack entertains the others with a story at lunch. We don't hear all the details, but involved a bunch of naked people and something with tusks.
Mook Promotion: Margaret, by virtue of being the only survivor of the Slitheen seen previously.
Oh Crap: Implied by the offscreen dropped teacup.
Pet the Dog: Margaret Blaine decides not to kill an Intrepid Reporter when she reveals that she's pregnant. Subverted when the Doctor accurately accuses Margaret of only doing it to balance the evil things she's about to do.
Poisoned Chalice Switcheroo: Margret / Blon tries this on the Doctor by poisoning his glass but it fails as he switches the glasses when he turns back to her.
Raise Him Right This Time: The Doctor and co. find someone to do this for Blon between episodes.
Running Gag: One that the new series likes to play with:

"Just go in there and tell her the Doctor's here."
"Doctor who?"

Shut UP, Hannibal:
- The Doctor reminds Margaret that for all her pleas for mercy, she's doing it through the lips of a woman Margaret killed.
- Blon / Margaret gets one herself. After the Doctor takes her Pet the Dog argument apart, she retorts that only a killer would know that and brings up his status as a Walking Disaster Area.
Teleporters and Transporters / Teleport Spam: Extensively. A particularly funny sequence has Margaret continually teleport herself while running away from the Doctor, but a poke on the sonic screwdriver has her immediately rematerialize running towards the Doctor.

The Doctor: I can do this all day.

Whatever: Jack throws Mickey bitchy "W" hands in response to the page quote.
What Do You Mean It's Not Awesome?: Margaret/Blon intends to leave the earth by using the nearby rift and blow up earth with a pice of technology that looks like a Goddamn Surfboard.
What the Hell, Hero?: Mickey really lets Rose have it in this episode, and you can't blame the guy. He spent a year not knowing where she was and everyone thought he'd killed her! She gave him a kiss and a smile and ran off with another guy, making him feel like he was nothing, and the worst thing is, she actually expected him to wait for her.
What Measure Is a Non-Human?: When everyone's angsting about having to take someone to their execution - even someone who's already tried to destroy a planet - Mickey tries to justify it with "She's not even human." It's clear he's only trying to convince himself.
Xanatos Gambit: A classic. Margaret rigged the surfboard thing to open the rift even if she was captured, by drawing on the alien power source she knew would need to be present to have facilitated her being captured in the first place -- since it was the Doctor, that meant the TARDIS. Brilliant.