After a year of searching for the Quantum Nexus, most of the tribe has split up. Jordan and Ami have gone to France, Kat is sorting out the nuclear power plants but everyone else reunites when they realize the key from Doomsday Dora fits into a stone head. But the head is in a stadium owned by Fizzy and there is also the matter that there is a traitor within their tribe. Reese is captured and the dims threaten to feed her to the lion if the Sparticles lose the fight. The lion is revealed to be a hoax and Holly is revealed to be the traitor, accepting a bag of Fizzys for doing a job for Fizzy. She vows to find the Quantum Nexus first and destroy it to determine the adults never return. She and Serena take off and the Sparticles take the Stone Head back to the Spartivan and set off on a race to the Quantum Nexus.

• Jon East, Jonathan Fox Bassett, Tim Whitby

• Annette Badland
• Larissa Wilson
• Jerome Holder