When he is thirteen, Lorcas' father gives him a rock. But not just any rock - this one is the cornerstone of an ancient castle. Lorcas ignores it for many years; after all, what can be done with a big rock on a hill? But eventually he begins to explore its origins, and then he begins to rebuild the castle - one stone at a time. As the castle grows, so does a spirit that lives inside its stones. As Lorcas develops a connection with that spirit, and with a 600-year-old shadow that speaks for it, he gains surprising powers - for a price. And the castle's plans for itself, for Lorcas and his friends, and for life on earth become clear. Would the castle have been better left unbuilt?
In 'The Delving', Lorcas' adventures with Rook, Zumar, and the rest of the entourage continue. The Knights are determined to destroy the castle, and Lorcas is determined to see the construction through to its end. Things seem to be going well: great underground chambers are delved, albeit haunted with scuttling creatures and mysterious winds; there are more discoveries in the Keep and Perry's house; and Lorcas has a new girlfriend to keep him busy. But disaster is looming. Will the Knights finally be successful in their quest to save the Earth in its natural form, or will Rook's power be too great in the end?