Merlin: Season 3, Episode 10

3 - 10: Queen of Hearts

When Morgana begins to have visions of a future with Gwen as the queen of Camelot, she desperately seeks to prevent them. Tricking Gwen and Arthur into a trap to expose their secret relationship, she succeeds in convincing Uther that Gwen is a witch who must be burned at the stake. Merlin must quickly devise a plan to save Gwen, but it leads to disaster for himself.