A wizard named Merlina, granddaughter of Merlin, attempts to flee from a black knight and his forces. Cornered, she performs a spell calling forth a champion to save her, summoning Sonic the Hedgehog. As they retreat, Merlina explains to Sonic that the black knight is actually King Arthur, who has been corrupted by the immortality granted by Excalibur's scabbard, and that Sonic must defeat him to restore peace to the kingdom. With Sonic's speed alone being insufficient to defeat the King, he takes up the talking sacred sword Caliburn. At Caliburn's suggestion, Sonic meets up with the Lady of the Lake, Nimue (Amy Rose), who tests Sonic to prove he is a worthy Knight. After completing her tasks, Nimue tells him that he must collect the other sacred swords wielded by Lancelot, Gawain, and Percival of the Round Table in order to dispel the immortality granted by Excalibur's scabbard. Defeating each of the Knights, Sonic claims all three swords and challenges the King once more, destroying him.
