As Merlin’s powers decline, one of his former students reappears at the right time. The magician decides to entrust him with the training of Arthur and Morgana and the protection of the kingdom before leaving Camelot. Refusing to abandon Merlin to his fate, our heroes quickly discover the duplicity of the magician who found a way to steal the powers of her former master… but who ultimately can do nothing against the strength that Arthur’s friendship gives her for him.