Merlin - The Darkest Hour (Part One)

Probably one of the most frightening episodes of Merlin with the introduction of a new foe, the Dorocha.  These are ghost-like wisps of evil that kill all they touch.  They look like the angels of death from Raiders Of The Lost Ark.  They only come out at night and can be frightened off by flame.
They were brought into the world by Morgana who tore open a rift between our world and the spirit world with the final sacrifice of her mortally wounded sister.
Uther is a dried shell of a man, destroyed by Morgana's betrayal, lost in his mental anguish.  Arthur must perform the impossible for the safety of all in Camelot and defeat a creature that swords have no effect upon. The only assistance he has in running the kingdom is from his uncle, Argravine, but what is his true agenda?
As more people are dying at the touch of the Dorocha, Arthur, Merlin and the Knights of Camelot head out to the Isle of the Blessed to attempt to repair the rift in the only way they know how, with a sacrifice.  Arthur is prepared to do it for his kingdom, but Merlin is ready to jump in before him.
However, one night, the band are attacked while holed up in a ruined castle and Merlin jumps in front of Arthur and takes the full brunt of a Dorocha attack.  The episode ends with him frozen and on the edge of death.
Political intrigue, horrific creatures and unselfish bravery are all part of a great season opener.