Episode 7 of 13.
First transmission on Saturday October 23, 2010 (UK)
The official details about the episode are as follows…
3.07 The Castle of Fyrien
Gwen faces an impossible dilemma when she is forced to choose between saving the lives of her estranged brother, Elyan, or Arthur, as the mystical adventure series continues.
With one of them certain to die at the hands of Cenred, who will Gwen choose: the love of her life, or her only sibling?
Loyalty and friendships are tested to the limit as Arthur, Merlin and Gwen work together to try to find a way out. But, with Morgana and Morgause doing all they can to scupper their plans, will good conquer evil or will Gwen lose someone she loves again?
Gwen is played by Angel Coulby, Elyan by Adetomiwa Edun, Arthur by Bradley James, Cenred by Tom Ellis, Morgana by Katie McGrath and Morgause by Emilia Fox.