We can expect a tense episode of Merlin in two weeks’ time, if the episode description of the fifth episode in series 5 is anything to go by.

Although the episode title has yet to be revealed (watch this space), CultFix has released the episode description for 5×05:

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.

What is this great sacrifice which Arthur must make?! And if Arthur can’t, will Merlin make the choice for him – at the “highest price”? Is this someone’s death, or will Merlin risk revealing his magic? The description also mentions that Merlin can save Arthur from his destiny, so perhaps this decision has to do with Mordred?

The Great Dragon will also appear in this episode – hopefully to offer Merlin some much-needed guidance on whatever tough decision he has to make.

Note that the BBC is once again pushing Merlin’s air date slightly; while Saturday’s episode “Another’s Sorrow” will air at 20:20 GMT, this episode (which airs November 3) will begin at 20:15 on BBC One.