Jack Mason has grown up as an acrobat in a circus. Now, after the tragic death of his parents, he must live inside the gloomy walls of Sunnyside Orphanage in London, a city of fog and snow, filled with airships, steam cars and metro towers that stretch into space. Luckily for Jack, he's taken under the wing of the brilliant and eccentric detective Ignatius Doyle. A girl named Scarlet Bell comes seeking the great detective's help. Her father has been kidnapped, and the future of the world itself may be at stake. Is the evil hand of Professor M pulling all the strings? Mr Doyle and Jack know there is no time to lose.