Season synopsis
Contains spoilers for this season and earlier seasons.
A year after Morgana’s betrayal, Arthur is carrying more of Camelot’s rule while Uther remains broken by what happened. Lancelot gives his life to repair the veil between worlds after the Dorocha threaten the kingdom, a loss that later matters when Morgana sends a shade wearing his face back to court. On Arthur’s birthday, an assassin sent by Odin wounds Uther. Arthur seeks a sorcerer to heal his father; Merlin approaches him disguised as an old man, and the spell briefly works; an enchanted charm around Uther’s neck reverses the healing, and Uther dies. Arthur becomes king, with Agravaine, his uncle, serving as a trusted adviser who is secretly allied with Morgana.
Morgana and Agravaine exploit Arthur’s trust and manipulate Gwen with an enchanted bracelet, making her appear to betray him with the Lancelot shade. Merlin recognizes that the returned knight is not the living Lancelot, but he cannot prevent Agravaine from arranging for Arthur to see the kiss. Arthur banishes Gwen. After the shade’s death, Merlin briefly awakens Lancelot’s true self before the funeral, and Lancelot thanks him. Arthur faces hard tests as king, including a confrontation with Queen Annis and the threat of Morgana’s growing power.
Morgana and the Southron warlord Helios attack and seize Camelot, forcing Arthur, Merlin and their allies into exile. Agravaine pursues them, but Merlin reveals his magic and kills him. When Arthur doubts his right to rule, Merlin arranges for him to draw Excalibur from a stone, restoring his confidence before they lead the return assault. Arthur retakes Camelot and his crown, marries Gwen, and she is crowned Queen of Camelot. Morgana is defeated and left wounded, but survives.