Merlin Series 4 Poster

Series 4 of Merlin will air in autumn 2011. It began on 1 October 2011 at 7.50 on BBC One. The series was originally cut to ten episodes from the previous series' 13 due to financial issues. However, Johnny Capps revealed on 18 March 2011 that the show has been increased to its original 13 weekly episodes, opening with a two-parter.[1] Filming started in mid-March 2011 in Cardiff, Wales and Pierrefonds, France This season is said to be darker and more mature than the rest, with the other three having a few violent scenes, and this one having much more. Most characters will show a darker side to their personality. The official tagline for the fourth series is: The Darkest Hour Is Just Before The Dawn.[2] At the SDCC Merlin Panel, it was confirmed that due to the show's increasing popularity, a fifth season has been commissioned by the BBC, and is likely to air the same time next year.



With Uther a shadow of his former self and unable to rule Camelot, it comes up to Merlin and Arthur to protect the kingdom from any possible threat and enemy.

Meanwhile, Morgana continues to take revenge on Camelot and Agravaine, a relative of Arthur, arrives to support him but is he a relative to be trusted?

Other Previews

Cast to Appear

Main Cast

Recurring Cast

Rumoured Cast

New Cast


Please put only officially released synopses in the episode description fields. You can find them here, new ones will be released every Thursday from now on until the series ends.

No. Title Director Writer Original Air Date UK Viewers (millions)
1 The Darkest Hour - Part 1 Alice Troughton Julian Jones 1st October 2011 6.40
Merlin faces his toughest challenge yet when Morgana's blinkered determination threatens not only Arthur's future, but also the very balance of the world. With her magic stronger than ever, the sorceress summons the mighty Cailleach to tear open the veil between the worlds.

Hellish creatures pour forth, killing all who succumb to their touch. With Uther a shadow of his former self, it falls to Arthur and his loyal knights, including Lancelot, to protect the kingdom.

But it will take more than just swords to vanquish their enemy and Merlin is shocked to the core when he discovers the only way to restore the equilibrium requires a sacrifice of unimaginable proportions...

2 The Darkest Hour - Part 2 Alice Troughton Julian Jones 8th October 2011 5.54
The kingdom is on the brink of collapse and Morgana poised to strike. As Lancelot races back to Camelot with the dying Merlin, Arthur must continue on his mission to vanquish the Dorocha without them. Though the Knights know their journey to the Isle of the Blessed is fraught with danger, none could anticipate the sacrifice Arthur intends to make there.

Friendship and loyalty are tested to the limit, but in the end, it's the power of love that changes all their lives for ever.

3 The Wicked Day


Alice Troughton Howard Overman


15th October 2011
The mighty citadel is buzzing in anticipation of the Prince's birthday celebrations, as the fantasy drama continues. But Arthur's old adversary, Odin, promises to ensure this is one party Camelot will never forget – for among the assembling guests lurks a deadly assassin set to strike.

As the dust settles, Camelot is left devastated. Just how far is Merlin prepared to go to put things right; would he really risk everything and reveal his secret?

4 Aithusa


Alex Pillai Julian Jones 22nd October 2011
The mysterious Julius Borden arrives in Camelot with news of a magical secret that threatens to change the landscape of the kingdom for ever, as the fantasy drama continues. He has located the final part of the key to the tomb of Ashkanar – an ancient mausoleum which holds a very special treasure: the last remaining dragon's egg.

Merlin is understandably drawn in by Borden's news and promises to help him. But just who is this enigmatic stranger and, more importantly, what does he really want with the egg?

5 Episode 4.5 Alice Troughton Jake Michie 29th October 2011
For the first time since his coronation, Arthur finds out what it's really like to be King, as the magical drama continues.

Arthur faces his first true test as King when he incurs the wrath of the formidable Queen Annis.

With the lives of thousands hanging in the balance, Arthur must find the strength to be his own man and become the leader Camelot so desperately needs.

6 Episode 4.6 Alex Pillai [6] Jake Michie 5th November 2011
7 Episode 4.7 Julian Jones 12th November 2011
8 Episode 4.8 19th November 2011
9 Episode 4.9 26th November 2011
10 Episode 4.10 Jeremy Webb 3rd December 2011
11 Episode 4.11 Jeremy Webb 10th December 2011
12 Episode 4.12 Alice Troughton


17th December 2011
13 Episode 4.13 Alice Troughton 24th December 2011


  3. 3.0 3.1 3.2 Merlin, Series 4, The Wicked Day (2011-10-07)
  4. 4.0 4.1 Network TV BBC Week 43: Saturday 22 October 2011 (2011-10-07)
Series 4
The Darkest HourThe Wicked DayAithusaHis Father's SonA Servant of Two MastersThe Secret SharerLamiaLancelot du LacA Herald of the New AgeThe Hunter's HeartThe Sword in the Stone
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