A gripping new fantasy adventure from bestselling author A J Hartley that will appeal to lovers of Artemis Fowl and Mortal Engines. The problem with doors is that they open both ways. There are monsters inside, and some of them are trying to get out...

A gripping new fantasy adventure from bestselling author A J Hartley that will appeal to lovers of Artemis Fowl and Mortal Engines. The problem with doors is that they open both ways. There are monsters inside, and some of them are trying to get out...