With the final battle between the Light and the Dark soon approaching, Will sets out on a quest to call for aid. Hidden within the Welsh hills is a magical harp that he must use to wake the Sleepers--six noble riders who have slept for centuries.

The Dark has stolen an object of great power--a golden grail that holds a vital secret. Will embarks on a new quest to reclaim the grail, and to drive back the Dark once again. But first he will need the help of three former grail seekers: Jane, Simon, and Barney Drew.