King Arthur pulls the magical sword Excalibur from the Stone, proving he is the rightful king of Britain. He establishes his kingdom at Camelot and marries Guinevere. Arthur faces many threats to his rule, including five invading kings and a search for the Holy Grail. In his final battle, Arthur is fatally wounded fighting his nephew Mordred, who had seized power while Arthur was away. Arthur's knights take him by boat to the mystical island of Avalon, where he will one day return to rule Britain again.