'Merlin': 'Aithusa' in pictures
When the mysterious Borden - none other than Battlestar Galactica legend James Callis - arrives in Camelot with a dragon-based secret or two, Merlin is intrigued - but can the newcomer be trusted?
Merlin continues on Saturday at 8.15pm on BBC One.
> Merlin: 'The Wicked Day' recap
Take a look at a gallery of images from this week's Merlin below:
Copyright: BBC Shine/Nick Briggs