The Darkest Hour

 The Darkest Hour is the name of the opening 2 parter of the fourth series of Merlin. This story will presumably follow the reprecussions of the previous series finale. Colin Morgan has said it focuses on darkness and that Morgana will release monsters that only come out in the dark from the underworld.

Synopsis
Morgana will take the wounded Morgause to the Isle of the Blessed, Merlin is to face his toughest challenge yet when Morgana's blind determination puts at risk Arthur's future as well as the very balance of the world. Morgana uses powerful magic to tear "the mystical veil between our world and the next." The Cailleach a "terrifying gatekeeper to the spirit world and her people The Dorocha (or shadow people) creatures are released and wander around, killing everyone who succumbs to their touch. With Uther but a mere shadow of his former self, it comes down to Arthur and his loyal knights to safeguard the kingdom. However, swords won't be enough to vanquish the newest threat and Merlin is utterly shocked to find out what it'll take to restore the equilibrium of the world: a sacrifice of unimaginable proportions is required.

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.

Plot
TBA

Cast

 * Colin Morgan as Merlin/Emrys
 * Bradley James as Arthur Pendragon
 * Katie McGrath as Morgana Pendragon
 * Emilia Fox as Morgause
 * Gemma Jones as The Cailleach
 * Angel Coulby as Guinevere
 * Anthony Head as Uther Pendragon
 * Richard Wilson as Gaius
 * John Hurt as the voice of Kilgharrah
 * Rupert Young as Sir Leon
 * Santiago Cabrera as Sir Lancelot
 * Tom Hopper as Sir Percival
 * Adetomiwa Edun as Sir Elyan
 * Eoin Macken as Sir Gwaine
 * Nathaniel Parker as Agravaine
 * Katie Moore as Drea
 * Zee Asha as Audrey
 * James Greene as Carrier
 * Charlie Petryszyn as Rescued Child
 * William Rowlands as Rescued Child
 * Anya Davies as Rescued Child
 * Source- http://www.bbc.co.uk/programmes/p00kf3w5

Broadcast
October 1 2011