Story details for the opening episode of Merlin Series 5 have been revealed. It begins with the first of two-parter, Arthur’s Bane.

The epic fifth series of Merlin returns to a Camelot basking in the halcyon days of a new Golden Age. Three years on from the end of series four, Arthur has never felt stronger, with Queen Guinevere and the Knights of the Round Table at his side.

But even as Camelot flowers, so the dark seeds of her destruction are being sown. For in the frozen wastelands of the North, men are disappearing without trace. In search of answers, King Arthur and his Knights must undertake a dangerous mission to the unknown.

Colin Morgan is Merlin, Bradley James is Arthur, Angel Coulby is Gwen, Katie McGrath is Morgana, Richard Wilson is Gaius and John Hurt as the voice of the Great Dragon. Tom Hopper, Rupert Young, Eoin Macken and Adetomiwa Edun returns as The Knights of the Round Table. Special guest stars including Liam Cunningham as Ruadan, Lindsay Duncan as Queen Annis and Sophie Rundle as Sefa.

Arthur’s Bane: Part 1 premieres Saturday 6 October 2012 at 7.45pm on BBC1.