Young Merlin is a teenager, discovering and then learning to master his gift for magic. Magister Gaius, the learned court physician of king Uther Pendragon to whom he's assigned as humble page, teaches him medicine, coaches his magical self-study and warns for Uther's vicious aversion from magic. Merlin becomes servant to the noble but imprudent crown prince, Arthur, whose fate is linked with Merlin's.

Camelot holds it’s yearly sword tournament. Knight Armed usies a magical shield and is determined to win at any cost. Merlin is determined to prove that Valiant is cheating before Arthur is killed in a dual with him.

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. Under pressure Gaius admits sorcery as the likely cause. Uther states that this kind of magic undermines his authority, and worries that if he cannot find the culprit then people will turn to magic for a cure. He orders Arthur to conduct searches of every house in town.

Nimueh returns and she tricks Merlin into consuming some poison from a chalice and he becomes very ill. Arthur attempts to find an antidote but ends up walking into a trap set by Nimueh.

Merlin cannot understand why anyone would want to harm others with magic. Gaius tells him that magic corrupts, and is only as "good" or "bad" as its user. Their investigations are interrupted by Arthur and his guards, who search the house. Merlin panics because his book of sorcery is upstairs, but he manages to magically hide it while Arthur is distracted.

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 worry and on the other hand also the things also going to be going in the best way.

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. But why does the and what these things are going to same.

In the beginning also the and on the other hand also from Uther's guards- but the druid is executed. Uther declares that also other thanks also going to be happen in the same manner They must try and smuggle the boy from Camelot without being caught. But why does the Great Dragon insist that Merlin should not help

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 Kanen, 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 forces the young sorcerer into making a difficult choice: will he use magic to save the village and thus reveal his secret to Arthu

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 unwittingly helps a renegade sorcerer turn lead into gold, he is arrested and faces trial for treason. 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. Merlin uncovers a plot to kill Uther, but will he try and stop it- or sit by and let it happen

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.