The kingdom of Krull is under siege from an alien presence known only as The Beast. Reigning terror down from his black castle with his army of Slayers, the Beast is opposed by two kingdoms. Prince Colwyn (Ken Marshall) and Princess Lyssa (Lysette Anthony) decide to marry and unite the two kingdoms against The Beast. Determined to destroy the world of men, The Beast kidnaps the bride of the future king. Banding together with a troop of adventurers including a cyclops, a shape-changing magician, Kegan (Liam Neeson), and Rhun (Robbie Coltrane), Prince Colwyn set out to retrieve the magic Glaive, a weapon of mystic power which can destroy The Beast. Armed against all odds, Colwyn and his men must find the Beast and his fortress before it is too late to save Lyssa and the kingdom.