It's been one year since Morgana's betrayal. The full list of cast members is as follows: Main cast The attack is successful, Morgana disappears, and Arthur marries Guinevere. The night before the attack, Merlin secretly enters Camelot and places an enchanted stick figure under Morgana's bed that drains her of her powers. Merlin restores Arthur's faith in himself when he arranges for Arthur to pull Excalibur out of a stone. Agrivaine pursues him, but Merlin reveals who he is and kills him. Merlin enchants Arthur, who is angry and feels that he has not behaved like a king, to get him to leave Camelot. In the two-part finale of the series, Morgana and Agrivaine attack Camelot. It becomes quickly apparent to everyone but Arthur that Agrivaine is in league with Morgana and wants her to ascend the throne. Merlin, Guinevere, and Gaius assist Arthur as Camelot enters difficult times. With Morgana's powers growing rapidly outside Camelot, Merlin must be more cautious and vigilant to protect Arthur and prevent Camelot's destruction. Agravaine, Arthur's uncle, becomes Arthur's trusted advisor. Prince Arthur takes charge and later becomes king after his father's death. Plot Ī year has passed since Morgana betrayed Uther, who has been left heartbroken. Notable guest actors include Santiago Cabrera, Emilia Fox, Gemma Jones, Phil Davis, James Callis, Lindsay Duncan, Gary Lewis, Charlene McKenna, Janet Montgomery, Terence Maynard, Ben Daniels, Miranda Raison and Caroline Faber. Supporting cast members include Adetomiwa Edun, Eoin Macken, Tom Hopper, and Rupert Young. Nathaniel Parker joined the regular cast in this series (credited as such for the first time in 'Aithusa') and John Hurt returned as the voice of the Great Dragon. Credited as a regular, Anthony Head left the series after his character was killed off in 'The Wicked Day'. Series four stars the regular cast from the previous series including Colin Morgan, Angel Coulby, Bradley James, Katie McGrath, and Richard Wilson. Writers include Julian Jones (head writer), Howard Overman, Jake Michie, Lucy Watkins, and Richard McBrien.

The directors of the series include Alice Troughton, Alex Pillai, Justin Molotnikov and Jeremy Webb. The series producer was Sara Hamill, and executive producers were Johnny Capps and Julian Murphy.

It consists of 13 episodes originally shown on Saturday evenings on BBC One and BBC One HD (repeats shown on BBC Three).

The fourth series of the British drama series Merlin began on 1 October 2011 with the episode 'The Darkest Hour - Part 1'.

Merlin season 4 episode 12 full