Excalibur

Nimueh is back to her evil work, to gain revenge against Uther. To kill him, she conjures up a dead knight, who offers his gauntlet for someone to come and fight him to the death; as knight after knight fight and die at the Black Knight's hand, Arthur becomes angry, and we discover the truth of Nimueh and about Arthur's birth. Meanwhile Merlin discovers the knight is a dead man and no mortal weapon can kill him, can Merlin discover a way to kill the Black Knight?