The one where the Doctor, Rose, and Harriet Jones are trapped with farting aliens in Downing Street, and the fate of Earth comes down to Mickey and a computer password.
Short Synopsis
The Slitheen reveal themselves as big green aliens in ill-fitting people suits. Their plan? Trick the world into nuclear war so they can sell the irradiated Earth for scrap. The Doctor, Rose, and Harriet team up while Jackie and Mickey get roped into the fight back home. In the end, Harriet Jones saves the day (remember her name).
Extended Storyline
We pick up exactly where Aliens of London left off: the Doctor, Rose, and Harriet Jones are cornered in Downing Street by the Slitheen, who’ve just unzipped their skins and gone full green goblin.
The Slitheen are gleeful about their scheme: Earth’s governments will believe hostile aliens have invaded, and in the panic they’ll hand over nuclear launch codes. Once the planet is reduced to ash, the Slitheen will sell it off piecemeal as radioactive real estate. Yes, they’re basically intergalactic house-flippers with a fondness for mass extinction.
Our heroes run for their lives through Downing Street’s corridors (which, for budget reasons, look suspiciously like a BBC office block). The Slitheen prove surprisingly agile for giant rubber suits, though still prone to giggling and farting.
Back at the Powell Estate, Jackie Tyler is having her worst day: her daughter’s been gone for a year, her daughter’s alien boyfriend has dragged her into chaos, and now actual aliens are on the telly. Mickey, still “Mickey the Idiot,” gets recruited by the Doctor via cell phone. His mission: hack into UNIT’s military systems. Mickey, of course, protests — “I’m not a hero.” The Doctor retorts: “You don’t need to be.” (This is the moment Mickey starts becoming more than just comic relief.)
Inside Downing Street, tension builds. Rose has her first brush with “Do you travel with the Doctor and die horribly?” Jackie demands answers, and the Doctor is forced to admit that yes, Rose’s life is always in danger when she’s with him. It’s raw, human, and adds weight to all the fart jokes.
Meanwhile, Harriet Jones shows her backbone. She’s just a backbencher MP, but she refuses to be cowed. She sides with the Doctor, helps Rose, and demonstrates the kind of courage that will (eventually) make her Prime Minister. The Doctor admires her grit immediately — though future Doctors may regret it.
The Slitheen, having locked the rest of the Cabinet in a room and electrocuted them (because why not?), are ready to trigger a global war. But the Doctor, ever the genius, calls Mickey and has him launch a missile at 10 Downing Street itself. Yes, the plan is literally: blow up the Prime Minister’s house while you’re inside it. Rose panics, but the Doctor promises the TARDIS can shield them. Harriet, because she’s amazing, simply goes along with it.
Mickey presses the big red button (after some coaching), the missile screams across London, and boom — Downing Street is toast, the Slitheen are barbecued, and the world is saved.
After the dust settles, Harriet Jones begins making her move toward leadership, introducing herself to every civil servant she can find: “Harriet Jones, MP for Flydale North.” The Doctor assures Rose she’s destined for great things. He isn’t wrong.
Jackie, however, isn’t convinced. She corners the Doctor and demands: what happens when her daughter doesn’t come back next time? The Doctor can’t promise safety, only adventure. Rose has to choose — stay with her mum, or keep running with the Doctor. She chooses the TARDIS. Jackie is devastated, but Rose is resolute.
Mickey, offered a spot in the TARDIS, declines — he’s not ready. But for the first time, he earns the Doctor’s respect. “You could,” the Doctor says. “But you won’t. And that’s fine.”
The episode closes with Rose dashing back into the TARDIS, ready for the next adventure, while Jackie watches in fear and Mickey in reluctant admiration.