When the Fires of Idirsholas burn for the first time in three hundred years, Gaius fears a sorcerer has revived the deadly Knights of Medhir. He’s right. Morgause (Emilia Fox) 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 a deep, unnatural sleep – all except for Morgana. Could she be behind the sleeping spell affecting the Kingdom? As Morgause and her Knights attack a helpless Camelot, Merlin’s loyalties are stretched to the limit.