School Reunion

The one where Rose gets jealous, Sarah Jane drops truth bombs, K-9 saves the day, and the Doctor’s emotional baggage is thicker than the school’s custard.

Extended Storyline

We open in Deffry Vale High School, where students are excelling at an alarming rate. (And yes, they’re eating chips that look so suspiciously tasty even Gordon Ramsay would be suspicious.) The Doctor has infiltrated undercover as… a physics teacher. Tennant in glasses, being all enthusiastic about quantum theory, is unfairly attractive — and Rose isn’t exactly focused on her history lessons either, since she’s stuck in a dull classroom giggling at him through the door.

But this isn’t just a “Doctor plays teacher” romp. Strange goings-on are everywhere. Kids are typing away at supercomputers, the lunch lady explodes after being splashed with oil, and the staff are clearly not human. Enter Mr. Finch, the headmaster, played by Anthony Stewart Head with a voice so velvety evil it practically purrs. He’s a Krillitanes — a shape-shifting bat-creature — and his staff are all the same. They’re using the children’s combined brainpower to solve the Skasis Paradigm, the equation that could control time, space, and every Starbucks line in the universe.

And then… she walks in. Sarah Jane Smith, investigative journalist and ex-companion from the 1970s, who immediately recognizes something weird is afoot. The reunion between her and the Doctor is equal parts warm, awkward, and heartbreaking. She thought he was dead; he, in typical Doctor fashion, just kind of forgot to call. Rose, meanwhile, doesn’t know how to handle the revelation that she’s not the first girl to step into the TARDIS. Jealousy levels: volcanic.

The tension boils over in a gloriously catty exchange between Rose and Sarah Jane, trading barbs about who knows the Doctor better. (“He replaced you with me.” “Well, he does that.”) Tennant, caught between his ex and current companion, looks like he’d rather be fighting Daleks.

But the real tear-jerker comes when Sarah Jane confronts the Doctor about leaving her behind. Elisabeth Sladen absolutely nails the scene — reminding both him and the audience of the cost of traveling with the Doctor. It’s emotional whiplash: one moment you’re laughing at Rose and Sarah Jane comparing notes, the next you’re crying because Sarah Jane represents every companion who was ever left to live a normal life while the Doctor kept running.

Meanwhile, Mickey tags along, desperate to prove he’s more than comic relief. And for once, he gets a win: he discovers K-9 Mark III in Sarah Jane’s car. The tin dog is rusty, wheezy, and falling apart — but he’s still got it where it counts. Rose is unimpressed, but the Doctor is overjoyed to see his old metal pal.

The Krillitanes launch their evil plan, luring the students into the computer lab to solve the Skasis Paradigm. The Doctor is tempted for a split second — imagine fixing the universe, bringing back Gallifrey — but Mr. Finch overplays his hand. The Doctor rejects the offer, proving that as much as he aches for his lost people, he won’t rewrite reality at the cost of freedom.

Cue action finale: the Krillitanes attack, the school goes full Buffy the Vampire Slayer, and K-9 saves the day by overloading the system and blowing up the school. It’s his noble sacrifice — “affirmative” never sounded so heroic. Sarah Jane is devastated, but the Doctor, ever the tinkerer, promises to rebuild him. And true to form, he leaves her with a brand-new K-9 Mark IV.

The episode closes with Sarah Jane reminding Rose that traveling with the Doctor isn’t forever — a bittersweet truth that hangs over the rest of the series. Mickey, meanwhile, decides he’s tired of being the tin dog — so he asks to join the TARDIS crew. For once, he’s not just the boyfriend left behind.