Simon Jane and Barney enlisted by their mysterious great-uncle arrive in a small coastal town to recover a priceless golden grail stolen by the forces of evil -- Dark. They are not at first aware of the strange powers of another boy brought to help Will Stanton -- nor of the sinister significance of the Greenwitch an image of leaves and branches that for centuries has been cast into the sea for good luck in fishing and harvest. Their search for the grail sets into motion a series of distubing sometimes dangerous events that at their climax bring forth a gift that for a time at least will keep the Dark from rising.
