Rulers from the Five Kingdoms converge on Camelot for a peace conference, including King Olaf and his spoilt, over-protected daughter Vivian. King Alined is also present, along with his jester, the wizard Trickler. He is a disruptive force who wants to cause discord between Olaf and Uther to gain ultimate power for himself. To this end he gets Trickler to bewitch Vivian and Arthur so that they fall in love and incur the annoyance of Olaf, who will challenge Arthur to a dual. This time it is down to Guinevere, rather than Merlin, to break the spell.
Watch It Here : Merlin Season 2 Episode 10