The Hot Zone is the eleventh episode of series one of the Sparticle Mystery. It was first broadcast on March 2nd 2011.
The Questers stop at a beach but soon realize theres harmful ammounts of radiation leaking from a nearby nuclear power station. Can they message the grown ups to stop a catastrophe happening? Meanwhile the Ranchers, living in a tent get a visit from Callum who has the dictaphone, only to get it stolen and have to gamble for it.
The Ranchers are now camping at a hill with other kids and have a pitiful garden compared to the hotel. The other campers notice a thing in the air so the Ranchers follow. It eventually lands and its Callum, looking for the Sparticles. A boy comes up claiming to know where they are but the real Sparticles come forward. Callum starts asking about the dictaphone for the Questers. Frankie who was looking for it meanwhile realizes its been stolen, by some henchmen, whos boss is called Fizzy. Callum and the Ranchers go off to search for the dictaphone.
Meanwhile, the Questers have stopped on a beach as there is a buzzing noise coming from within the van but they're having no luck locating the source of the noise. Holly is meanwhile writing postcards to her parents, despite the fact that they argue and that there is no way of sending the postcards which Kat points out. Kat asks for a spare and starts writing one and puts it in a bottle and throws it in the ocean along with Holly. Reese finds the source of the noise, a device from the underground bunker from the last episode. Reese notices they're near another ley line intersection. Kat realizes that the device is a device for measuring radiation and the fact thats is buzzing is a bad sign as its measuring radiation at a high level. Over a hill they discover a nuclear power station and she realizes its melting down. They quickly realize they need to leave the place which they do. They eventually come upon a tunnel which is blocked off, saying that its a hot zone due to radiation. Kat realizes that unless they attempt to stop the meltdown, they'll all die.
The Ranchers are walking up to a train and on further inspection its revealed its a club. Jeffrey waits outside with Liam and Frankie while Callum and Tia go inside. There is lighting, toy car racing and music inside. A boy stands up claiming to remember Callum, he is revealed to be Fizzy who sends a henchman to check for the dictaphone. Callum covers up the true purpose of the dictaphone.
The Questers find a message from the kids who parents worked in the area. Reese has an idea to get a message through using a wormhole which Kat decides to attempt. Sadiq reluctlantly drives the Sparty van through the barrier.
Fizzy meanwhile has a job for the Ranchers, to get the train working so he can make is club a touring club but theres a lock on some of the controls for the train. After Jeffrey says he doesnt trust him, Callum reveals one of Fizzys henchmen attacked him with a knife the last time they met.
The Questers are meanwhile driving through the town which is eerily abandoned while Ami reads a guide on how to survive a nuclear fallout. They go into a theatre where Sadiq finds a mechanism to raise the curtain and find Ami and Jordan who claim that certain types of clothes can protect from certain types of radiation. Reese finds the wormhole and sees Holly behind it who says the device is up to three. Sadiq is meanhwile annoyed at Kat for dragging them in here and bangs an xylaphone in frustration which gives Kat an idea to send a message using radio waves using the laptop Doomsday Dora gave them.
Callum has meanwhile almost sucessfully broken the lock and uses Frankies hairpin to finally break the lock. Tia has meanwhile stormed off after arguing with Callum. Callum gives the lock to Fizzy who decides to make Callum win back the dictaphone and they risk the paramotor and several items from Tia and Callums pockets. Liam and Frankie are outside trying to see in the windows but the security guard comes over and stops them. Inside Fizzy wins the game but Jeffrey decides to sacarfice himself to work for free for Fizzy for the dictaphone but Fizzy denies the offer. Tia and Jeffrey then go to break the bad news to Liam and Frankie.
Kat has meanwhile worked out a message using musical notes. Kat plays the message but they decide to leave after the device is up to level seven so they decide to get out of there.
Tia and Jeffrey are trying to plan how to get the dictaphone back and consider telling Fizzy the truth. Jeffrey decides to fight Callum but its in fact part of a plan.
They're just about to leave but the device is just touching off nine indoors so instead of heading outside, Ami leads Sadiq off with a plan.
Fizzy meanwhile has the paramotor and Callum gets walkie talkies for everyone and they've decided to use Fizzys train to escape. Liam is meanwhile inside the barn, having retrieved the dictaphone.
Meanwhile, Sadiq, in armour to protect him from radiation, gets the Sparty van up to the door and just as Kat and Holly are about to get into the van, they realize they've gotten a message from the adults as different music notes can be heard playing.
Back in the barn, the bodyguard guarding it hears noises and opens the doors which lets Liam escape with the dictaphone after distracting the bodyguard and getting on the train and Tia starts to reverse the train but realizes her mistake and drives it forward. Fizzy notices and attempts to run after them but falls off the platform running after them and they sucessfully drive away.
- Muna is mentioned in this episode
- The message sent works as in the episode the Sparticle Project, Kats dad gives her a code to shut down all the nuclear power stations just beofre he disappears.