When Simon's little sister is mysteriously snatched away to a dark other world, he is sent by a golden messenger on a dizzying quest to get her back. With him is Flora, whose brother has also vanished, and a strange boy who rescues them from a violent attack. To enter the land of the Broken King they must complete three tasks: Eat the Shadow. Steal the Sun. Break the Air. But how do they even begin? And what lies in wait for them, in the land of the Broken King?