The Doctor comes face to face with Danny Pink, the teacher Clara’s dating, as he fights to save the planet from a terrifying alien. And it’s not exactly amicable when the Doctor experiences a touch of the green-eyed monster!



Clara’s shocked when the Doctor turns up at her school posing as new the new caretaker, John Smith, and refusing to tell her what he’s up to.



But it soon turns out he’s on a hi-tech undercover mission to save Coal Hill School and the world from the Skovox Blitzer – a metal crab-like alien that has enough explosive in its armoury to take out the whole planet.



Using a special invisibility watch, he hopes to confuse and then destroy the creature without risking lives. However, suspicious of Clara’s relationship with the new ‘caretaker’, Danny secretly starts to follow him as he works on his covert plan.



But when Danny inadvertently tampers with the technology, he ends up putting Clara and the whole school in mortal danger!



With parents’ evening in full swing and the Skovox Blitzer stalking the school corridors, the Doctor must think of a new plan before its too late.



At the same time, furious with Danny’s meddling and believing he’s not good enough for Clara, the Doctor tries to outwit him in a bid to be number one in Clara’s affections!



As the seconds to global destruction quickly tick down, will the Doctor be able to put his jealousy to one side and work with Danny to save the world – and Clara?