在中世纪的英格兰,梅林和亚瑟王将邪恶的女妖摩根娜和她的儿子莫德雷德驱逐到宇宙的尽头。时间来到现代,为了复仇,摩根娜和她的儿子回到地球,决心摧毁亚瑟王和他的骑士的每一个后裔。In medieval England, Merlin and King Arthur banish the evil enchantress Morgana and her son Mordred to the ends of the universe as Morgana vows revenge. In present day, Knights descendant Penn doesn't take much stock in the legends of his supposed ancestors, even as the descendants meet in Thailand to practice fighting. But when Morgana and her son return to earth, armed with alien technology and hell-bent on destroying every last descendant of King Arthur and his knights, Penn must to come to terms with who he was born to be, and bring together the new Knights of the Round Table to save themselves and the earth from Morgana's total vengeance.