Guest starring James Callis as Julius Borden, Aithusa airs at 8.15pm on Saturday 22nd October on BBC One and sees the mysterious Borden arrive in Camelot with news of a magical secret that threatens to change the landscape of the kingdom for ever.

Are you looking forward to the episode? Let us know below…

> Order the Series 4 Volume 1 DVD on Amazon.

Watch the Series 4 trailer, with an exclusive introduction by Nathaniel Parker for CultBox…