The Sparticle Mystery - Season 1 Episode 4 -

Doomsday Dora's message has warned the children they must reunite the two parallel worlds quickly or adults and children will remain separated permanently. The ticking clock has started. The children decide to choose who goes on the road to the Sparticle Project and who stays behind to look after Liam and Frankie by an 'Apprentice'-style challenge to source power for the City Hotel.