Worldshaker

Col lives on the Upper Decks of the juggernaut Worldshaker, a mobile city as big as a mountain. He has been chosen as next Supreme Commander - but then a Filthy escapee from Below - a girl named Riff - appears in his cabin.

Will he hand her over, or will he break all the rules? Col's safe, elite world is about to fall apart.

Col and Riff led the oppressed Filthies to victory, but now the revolution on their mountain-sized juggernaut is falling apart. A saboteur strikes, and suspicion and paranoia reign. Will Riff deny her love and brand Col a traitor? Can anyone stop the extremists taking over? And can they defeat the Imperialist juggernauts massing for war?