Season synopsis
Contains spoilers for this season and earlier seasons.
Merlin comes to Camelot from Ealdor to study under Gaius, but Uther’s ban on sorcery makes the young warlock hide his gift. After Merlin saves Prince Arthur from an assassin, Uther appoints him as Arthur’s servant. The imprisoned Great Dragon tells Merlin that Arthur is destined to unite the land, so Merlin protects a prince who initially treats him as an irritating subordinate. Their uneasy partnership grows through threats that require Merlin to use magic without revealing himself.
Nimueh’s plots bring that danger close to home. Her enchanted egg contaminates Camelot’s water, and when Merlin secretly cures Gwen’s father, Uther blames Gwen and sentences her to death. Merlin and Arthur find the monster behind the plague and save her. Later, Nimueh poisons Merlin with a chalice; Arthur defies Uther’s order, retrieves a rare antidote flower, and Gwen helps get it to Merlin after Uther crushes it. Morgana’s prophetic dreams also hint at a power she does not yet understand.
When raiders threaten Ealdor, Merlin returns with Gwen and Morgana, and Arthur follows to help train the villagers. Merlin’s magic drives off the attackers, but William takes credit so Camelot will not condemn his friend. At the season’s end, the Questing Beast wounds Arthur. Merlin seeks water from Nimueh on the Isle of the Blessed, where a life must be exchanged for Arthur’s. Gaius secretly takes Merlin’s place; Merlin defeats Nimueh and saves him. The Great Dragon remains imprisoned.