Merlin orders King Uther's secret son Arthur to claim the throne after Uther is killed
After her home is ransacked, Guinevere flees to Camelot to be with her fiancé Leontes. Morgan invites Arthur to Castle Pendragon so they can get to know each other better.
Arthur is upset that he can't be with Guinevere, and in his grief, neglects his duties to the warriors. Angry with Arthur's lack of direction, Gawain shatters his sword.
Arthur learns that the villagers are trying to take the law into their own hands and hang a man they accuse of murder. So he tries to establish the rule of law and begins a trial.
Arthur and Guinevere bond with each other; Merlin goes to Ector's house to retrieve an essential tool for Arthur; and Morgan gains support with the people
Morgan invites the people of Arthur's court to Castle Pendragon for a feast, with a view of showing loyalty to her half brother. Later, an attack at the castle tests loyalties.
Morgan shapeshifts into Igraine while the real Igraine is held captive at Castle Pendragon. The men have a successful day hunting, and Leontes has a disturbing dream.
Harwel attacks one of Arthur's outposts, hoping to draw him out from Camelot to defend it. Meanwhile, Leontes is furious with Guinevere and Arthur.
In the series finale, Arthur is left alone to fight Harwel's men. Morgan has taken over Camelot and is stoking the rumour about Arthur and Guinevere.