Fair rating?The Darkest Hour: Part One
Merlin faces his toughest challenge yet when Morgana's blinkered determination threatens not only Arthur's future, but the very balance of the world. With her magic stronger than ever, the sorceress summons the mighty Callieach to tear open the veil between the worlds. Hellish creatures pour forth, killing any 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.
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#6In Season 4of 13 rated episodes
#29All-timeof 65 rated episodes
+0.1vs season avgSeason 4 averages 7.4
2011First airedOctober 1, 2011
Guest stars
Rupert Youngas Sir Leon
Eoin Mackenas Sir Gwaine
Tom Hopperas Sir Percival
Tomiwa Edunas Sir Elyan
Emilia Foxas Morgause
Santiago Cabreraas Lancelot
Zee Ashaas Audrey
Gemma Jonesas The Cailleach
James Greeneas Ferryman
Katie Mooreas DreaShows like Merlin
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