When young warlock Merlin arrives at Camelot, sent by his mother to start a new life, he finds himself in a place where magic is punishable by death. Yet when he finds the Great Dragon, Merlin's destiny becomes clear- he must use his magic to protect Arthur, son of Uther and future King.
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.
Camelot faces a double danger when a lethal plague starts spreading through the castle and Gwen is arrested for witchcraft. Merlin must team up with Arthur and Morgana to find the culprit behind the evil deeds.
As Bayard and the Knights of the Western Isles are welcomed to Camelot for a feast, Nimueh infiltrates Bayard's entourage and begins a plot to get revenge on Merlin.
Posing as a servant girl, she tricks Merlin into drinking from a poisoned chalice. Falling gravely ill, the only chance Merlin has is for an antidote to be prepared. Arthur takes it upon himself to retrieve the needed ingredients but, with Nimueh doing everything she can to thwart Arthur's quest, will they be able to save Merlin in time?
Merlin is saved from a terrifying winged beast by a heroic stranger- a young man named Lancelot, who dreams of becoming a Knight of Camelot. In order to thank him, Merlin provides falsified records of Lancelot's noble birth and Lancelot is accepted. However, with the winged beast- discovered to be a Griffin- still on the loose, Merlin's decision could have far-reaching consequences not just for Lancelot but for Camelot...
When Morgana falls ill, Gaius is unable to cure her. However, a mysterious physician named Edwin Muirden is able to make her well again. As Edwin charms his way into the court, Gaius becomes suspicious. But is there a darker motive at work?
Arthur and Merlin save a young woman and her father from a band of brigands. Arthur becomes quite besotted with the young girl, Sophia, and offers them refuge in Camelot. However, it's not just Merlin who is suspicious of the new arrivals- Morgana awakes from a nightmare about Arthur's death at the hands of a beautiful young woman to find Sophia is the girl in the nightmare...
When a druid and his boy apprentice are caught in Camelot, Morgana and Merlin hide the boy from Uther's guards- but the druid is executed. Uther declares that anyone harbouring the boy will be dealt with severely. They must try and smuggle the boy from Camelot without being caught. However, a visit to the Great Dragon reveals who the young boy is- he is Mordred, the future nemesis to Arthur...
Uther's past comes back to haunt him as a mysterious black knight interrupts Arthur's coming-of-age celebrations, throwing down his gauntlet and challenging the Knights of Camelot to combat. The Black Knight, seemingly unstoppable, makes easy work of his combatants. But who is the Black Knight, and why is Uther so uneasy?
Merlin's home village of Ealdor is attacked by raiders led by the fearsome Kanan, but Uther will not do anything to help- to cross into Ealdor, which is outside of Camelot's boundaries, would constitute an act of war. Merlin leaves Camelot to help to defend his home- and is surprised to find help from Morgana, Gwen and Arthur. However, an old friend of Merlin's forces the young sorcerer into making a difficult choice: will he use magic to save the village and thus reveal his secret to Arthur?
When Arthur kills a unicorn, he brings a curse upon Camelot. With the mythic city plagued by both famine and drought, time is short for the curse to be lifted. The mysterious Anhora, keeper of the unicorns, tells Arthur he is responsible for bringing the famine to Camelot- and to lift the curse, Arthur will be tested... but unless he makes amends for the killing of the unicorn, Camelot will be doomed.
When Gwen's father Tom helps a renegade sorcerer turn lead into gold, he is arrested and faces trial for sorcery. Despite pleas from both Arthur and Morgana, Uther is adamant- Tom will be tried and, if found guilty, will be executed. Morgana tries to help Tom escape but tragedy ensues... and Morgana becomes hellbent on revenge.
When out on a hunt, Arthur encounters a huge monstrous creature never before seen. Gaius realises it is a Questing Beast, a creature conjured from the nightmares of a long-dead king, whose bite is always fatal. When Arthur faces the creature again, it is vanquished... but Arthur is bitten and his life hangs in the balance. Merlin is told by the Great Dragon to seek the Isle of the Blessed, where members of the old religion have the power to save the future king. However, there is a price to pay. In order for a life to be saved, a life must be taken...