->''"The day I was born, I saved the world. Now I've helped to destroy it."''
Luke and Maria start their first day at their new school, but not everything is as it seems, the cafeteria food is mouldy, the air smells like batteries, people are spontaneously getting ill and [[SincerityMode worst of all]], the portly head teacher has gas problems. Aided by their new friend, Clyde Langer, Sarah Jane and the gang discover a sinister revenge plot engineered by the Slitheen, for what the Doctor did to another branch of [[Recap/DoctorWhoS27E5WorldWarThree their family]].
* AdventureRebuff: Both Sarah Jane and Maria try to make Clyde go away for his own good. [[CaptainObvious It doesn't work]].
* BlandNameProduct: Clyde's Wolverine brand body spray, a play on the real brand "Lynx".
* ContinuityNod: [[Recap/DoctorWhoS27E4AliensofLondon Slitheen]] [[Recap/DoctorWhoS27E5WorldWarThree in]] [[Recap/DoctorWhoS28E3SchoolReunion Downing Street]].
* EvenEvilHasLovedOnes: [[spoiler:The Slitheen beg Sarah Jane and the others to let the young Slitheen live]]
* EvilTeacher: The Slitheen pose as teachers [[spoiler: worldwide]] during their revenge plot.
* FatBastard: The Slitheen, as usual.
* ForeShadowing: The scene at the end when Clyde asks Mr. Smith where he came from and the computer responds by shocking him [[spoiler:hints at the reveal that Mr. Smith is secretly evil.]]
* HoldYourHippogriffs: "Oh, for the love of Clom!"
* IncestSubtext: Between Glune, the headmaster Slitheen, and Kist, the science teacher Slitheen, which might help explain why [[IncestIsRelative the Slitheen are so screwed up]].
* LargeHam: All of the Slitheen.
* NiceJobBreakingItHero: Luke gives the Slitheen the equations they need in response to a transparent ploy that you'd have to have been born yesterday not to see through. Unfortunately for Luke, he ''[[YoungerThanTheyLook was]]'' born yesterday.
* SecondEpisodeIntroduction: Clyde.
* SchoolForScheming: [[spoiler: The Slitheen have set up bases within schools worldwide to power their sun-draining machine.]]
* ShoutOut: "Let's have a ''HighSchoolMusical'' moment. [[SarcasmMode A group hug will sort everything out]]."
* TheNightThatNeverEnds: A variation, [[spoiler: instead of blotting out the sun, the Slitheen are trying to ''drain'' the sun of its energy.]]
* ToiletHumor: Luke doesn't understand it.