Thomas and Charlie are friends at a boarding school near Oxford, where the children of the rich and powerful are trained to be future leaders. Charlie is naturally good, but Thomas's father was accused of a terrible crime, and Thomas fears that the same evil lies coiled inside him. Then, on a trip to London - a forbidden city shrouded in darkness - they learn all is not as it appears. So begins a quest to understand the truth about this world of smoke, soot and ash - and perhaps to change it. 'Mesmerising and imaginative ...a novel that tackles the most fundamental question of good versus evil' Hannah Beckerman, Observer. 'Like an adult version of the Harry Potter books with a touch of Dickensian dystopia ...a sheer delight' Maxim Jakubowski, Lovereading. 'A novel that stays in the imagination long after it is read' Adam Roberts, Guardian.