The story is based on the myth of King Arthur. A young, inexperienced squire Valiant, masquerading as Sir Gawain, is sent to accompany the Wales princess Lady Ilene, a guest at Camelot, on her way back home. Little does he know that meanwhile, Arthur's wicked sister Morgan le Fay has retrieved a spellbook from Merlin's tomb and convinced the Viking warlord Sligon, ruler of the kingdom of Thule, to steal the magical sword Excalibur during a joust tournament.