An armour-clad figure strides into Camelot, killing five guards and besting Arthur in single combat. This is Morgause, whom Gaius and Uther know to be Morgana's half-sister. Before she leaves the court, she gives Morgana a magic bracelet which helps her sleep and challenges Arthur to set out on a quest. He duly complies. He and Merlin arrive at Morgause's castle where she evokes Arthur's late mother, Ygrain, who tells him Uther sought magic to produce an heir and let her die that Arthur might live - the terms of the deal. A distraught Arthur accuses Uther of hypocrisy and tries to kill him, but Merlin dissuades him, telling him that Morgause tricked him with an illusion in order to destroy Camelot. Uther expresses his thanks to Merlin, ironically believing him to be an opponent of magic.
—don @ minifie-1