Col lives on the Upper Decks of the juggernaut Worldshaker, a mobile city as big as a mountain.  He has been chosen as the next Supreme Commander – but then a girl, Filthy, escaped from Below appears in  his cabin. “Don’t let ’em take me!’ she begs. Will he hand her over or break all the rules. Col’s safe, elite world is about to fall apart. Steampunk fantasy.