Merlin series 5 episode 2 airs on 13 October at 8.25pm to 9.10pm on BBC One.
Ancient prophecies of Mordred weigh heavy on Merlin, for not even he can sway Arthur from his chosen path.
As dawn breaks across the icy tundra, Merlin and Arthur are close to exhaustion. With each tortured step, the fortress of Ismere looms ever nearer and Merlin’s fear intensifies. What game is Mordred playing? And what powerful secrets are Morgana and the druid Ruadan (Liam Cunningham) searching for amongst its twisted catacombs? It seems like this time, not even Merlin can stop Arthur from walking right into the lion’s den… For in this bleak and transient wilderness, only one thing is certain: the great trial for Albion has finally begun.
Colin Morgan is Merlin, Bradley James is Arthur, Angel Coulby is Gwen, Katie McGrath is Morgana, Richard Wilson is Gaius and John Hurt as the voice of the Great Dragon. Tom Hopper, Rupert Young, Eoin Macken and Adetomiwa Edun returns as The Knights of the Round Table. Special guest stars including Liam Cunningham as Ruadan and Sophie Rundle as Sefa.