Story details for the fifth episode of Merlin Series 5 have been revealed.

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 (Frances Tomelty, Sian Thomas, Helen Schlesinger) 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.

Colin Morgan is Merlin, Bradley James is Arthur, Angel Coulby is Gwen, Katie McGrath is Morgana, Richard Wilson is Gaius and John Hurt is the voice of the Great Dragon. Tom Hopper, Rupert Young, Eoin Macken and Adetomiwa Edun return as The Knights of the Round Table. Special guest stars include Frances Tomelty, Sian Thomas, Helen Schlesinger as the Disir and Andrew Tiernan as Osgar.

Episode 5 airs Saturday 3 November 2012 at 8.15pm on BBC1.