Agents of the Dark steal the golden grail and are trying to get the manuscript that translates it. It's up to Simon, Jane, Barney, and Will to battle the forces of evil. Jane is drawn into a relationship with the mysterious Greenwitch, guardian of the manuscript. Great-Uncle Merry enlists the sleuthing skills of his niece and nephews, Jane, Barney, Simon, and Will Stanton, the new Old One. With the ancient grail in their possession, the Dark is just one step away of destroying all that is good if they can get their hands on the manuscript.
The document, which will provide the translation of the carvings on the grail, was tossed into the sea and is now protected by the Greenwitch. In the small village of Cornwall, only the women are allowed to attend a ritual to pay homage to the Greenwitch, and Jane is invited. Jane feels sad for the Greenwitch, and when it is her turn to make a customary wish, she wishes the Greenwitch could be happy. Thus, a bond is created between the two.