Imagine a world in which every bad thought you had was made visible. Where anger, hatred and envy appeared as thick smoke pouring from your body and soot on your skin. With society controlled by an elite who have learned to tame their darkest desires. 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 murder 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 that all is not as it appears. So begins a quest to find the truth, and to learn what lies beneath this world of smoke, soot and ash...'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