Merlin: Season 2, Episode 8

2 - 8: The Sins of the Father

When a mysterious warrior woman challenges Arthur to a duel, no one could possibly predict the devastating chain of events that is set in motion - least of all the young Prince himself. Arthur and Merlin soon find themselves on a strange quest to find out the truth about Arthur's mother at the behest of the beautiful Morgause. Through her, Arthur discovers a dark secret which threatens to bring about the downfall of the kingdom.