When Hop awakens in an ancient labyrinth, he has no memory of his life before, or how he got here. He does not recognise the mysterious girl trapped with him. And he certainly cannot identify the shadowy figure stalking him, whispering terrible things . . . But there is one thing he is certain of. He must escape. The only way out of the labyrinth is through The Bone Door. But it lies behind a series of other locked doors hidden across an array of strange realms. To open the way, Hop must complete impossible tasks before his time runs out. As Hop travels deeper, he discovers that he and his companions may be more connected to the place and its horrors than he could ever imagine. Unless Hop is able to unravel the true mystery of the labyrinth, including his own role within it, the Bone Door and any hope of escape will be lost forever.