Merlin concludes the fourth series with an epic two-parter The Sword in the Stone. With Morgana at the head of a vast Southron army, a deadly net is closing in around Camelot. When the sorceress strikes, the ferocity of her attack forces everyone to run for their lives – even Arthur. But Morgana won’t let him escape that easily. And so begins a chilling hunt. Can Merlin save the King from Morgana’s clutches? Or has Arthur’s luck finally run out?

A first look at episodes 12 and 13 can been seen below.

Merlin finally gets a new look!

Morgana and her new right hand man Helios (Terence Maynard).

Surprise, surprise Agravaine is up to no good.

Tristan (Ben Daniels) and Isolde (Miranda Raison).

Arthur’s going to need all the help he can get.

The Sword in the Stone Part 1 airs 17 December at 8.10pm on BBC1. Part 2 airs 24 December at 8pm on BBC1.