A knight named Valiant arrives in court to compete in a sword-fighting tournament. Valiant holds in his power an enchanted shield which causes great harm to his opponents. Merlin's attempts to warn everyone fall on deaf ears- and Arthur is next to face Valiant.
Merlin is a young warlock who arrives in the kingdom of Camelot after his mother arranges for him to stay with the court physician, Gaius. He discovers that the king, Uther Pendragon, has outlawed magic and imprisoned the last great dragon deep under the kingdom.
The dragon tells Merlin that he plays an important role: to protect Uther's son, Arthur, who will bring forth a great kingdom. When Merlin meets Arthur, he believes that he is arrogant and Arthur, likewise, views Merlin as subservient. Merlin must keep his magic secret or face being executed by Uther.