After Gwen is snatched from Camelot, Merlin knows that Morgana must be responsible. Arthur is determined to rescue his Queen but she is locked in the Dark Tower, a place that haunts the dreams of men.

Previously on Merlin Season 5 Episode 5 “The Disir”, In the inky depths of an ancient pool, three soothsayers cast a dark judgment upon the king of Camelot. But despite Merlin’s warnings, headstrong Arthur refuses to take the words of the Disir seriously, and their fury rains down on Camelot. Only the greatest sacrifice can appease them, and with the kingdom in jeopardy, is it one that Arthur is prepared to make? Faced with the king’s uncertainty, Merlin has just one chance to save him from his destiny – but this decision comes at the highest price.