Many years pass. Merlin is brought before the tyrant King Vortigern, who is having problems constructing his castle. Merlin tells the king his vision: a red dragon representing Uther Pendragon defeats the white dragon that represents Vortigern. Mab tells the king that he can vanquish Uther by sacrificing Nimue to a dragon, in the hope that Merlin will break his vow not to use magic. Merlin uses magic to save Nimue and she is sent to Avalon to recover from her burns. Merlin asks the Lady of the Lake for help, and she gives him the magical sword Excalibur.