Sorry for my English, I am not a native speaker.
This episode was great.
For the first time, Merlin dares to inform Arthur that some noble relative is betraying him (no less than his wife). This shows how much their relationship has evolved. Arthur was suffering so much when he was with Gwen, pretending that everything was fine!
I loved the scene with the creepy witch. Merlin showing who is the boss!
It was plenty of funny moments, too. However, I think the old-woman-Merlin was a little bit too comical and it made difficult to believe that Merlin was casting an extenuating spell or that Gwen was in great danger. Maybe this was a good occasion for Merlin to reveal his powers to Arthur. By the way, Mordred's face when he sees Merlin turned into an old woman was priceless.
Last episode, I asked myself if there were any other gods (other than the vengeful Triple Goddess). I am glad to see that there is a White Goddess who seems to be kind, since she appears as a beautiful healing light.
I wonder why Aithusa looks so sick and why he can't speak. I know that he was trapped, but he already looked sick before. Maybe Morgana doesn't know how to take care of a baby dragon, despite how much she loves him.
Many questions and few episodes left. I am crying; I don't want Merlin to end!!!