1x8 - Camelot

Morgan fools Camelot with her disguise, even Merlin. However, after Redwald, a little orphan boy, whom she and Merlin have helped celebrate his birthday, accidentally dies because of her, Merlin has his suspicions. Vivian, feeling sorry for Igraine, releases her to confront Morgan but Morgan, in her guise as the queen, has let slip to Leontes his wife's indiscretions with Arthur.