Episode 12 of 13 – The Fires Of Idirsholas. First transmission on Saturday December 12, 2009 (UK)
The official details about the episode are as follows…
When the fires of Idirsholas burn for the first time in 300 years, Gaius fears a sorcerer has revived the deadly Knights of Medhir, in the penultimate episode of the magical family drama. Morgause has returned, hell-bent on ending Uther’s reign.
Arthur and Merlin ride out to face the Knights and barely escape with their lives. Upon returning home, they find everyone in Camelot is under a strange enchantment – all except for Morgana. Could she be behind the magic which threatens the Kingdom? As Morgause and her Knights attack a helpless Camelot, Merlin’s loyalties are stretched to the limit.
Gaius is played by Richard Wilson, Morgause by Emilia Fox, Uther by Anthony Head, Arthur by Bradley James, Merlin by Colin Morgan and Morgana by Katie McGrath.