Cavall and King Arthur embark on a quest to find a legendary grail... King Arthur's dog, Cavall, and the rest of Camelot thought their troubles were behind them after they defeated the Night Mare. But when Arthur's son, Mordred, falls gravely ill, it seems that something sinister is afoot in Camelot once more. The only thing that can cure Mordred is an ancient artifact hidden deep within the fay forest--an artifact that's been missing for centuries...