Modern-day Nathan, 11, stumbles upon the ruins of a dark chapel in the deep woods, and becomes haunted by dreams of a grail cup filled with blood. His mother, Annie, runs a second-hand bookshop in the small, quiet town of Thornyhill, and they are unknowingly protected by the benevolent Bartlemy Goodman, an excellent cook and dabbling wizard. Nathan's dreams become more vivid and bizarre as he begins dreaming of another world, Eos, in another parallel dimension, which has poisoned itself and is dying, despite their technological advancement and near-immortality. Soon Nathan realizes that he is actually being transported to real places, and is able to interact and change things in this world. It all seems to be tied to the grail of his dreams, the Greenstone Grail, which was protected by a Thornyhill family for centuries until it was lost to them.