Arthur and his men learn of an attack at Bardon Pass and ride out to defend it. Merlin realizes he's been seduced by a shape-shifting Morgan. The men begin to lose faith in Arthur after learning of his betrayal.
Morgan convices Igraine that she is just hallucinating and escapes Camelot now in her (Morgan's) form. When Merlin and Igraine confront Morgan at her castle about this, she and her followers arrest them. She then anonymously stages a raid at Bardon Pass, hoping that Arthur will be inadequate to stop it, positioning her to become acknowledged as the better ruler of Camelot, and proceeds to travel to Camelot with her new prisoners, Merlin and Igraine.
Leontes confronts Guinevere about her relationship to Arthur, and then confronts Arthur about it. During the battle Kay is shot by a arrow, becoming in desperate need of medical attention. Arthur and his friends realize that the only way that they will succeed is if one of them stays behind. Arthur volunteers, and his friends depart the battle grounds, and Arthur prepares for a full out battle to the death with Morgans army.
