Ivy has spent years looking for her birth mother, but when she finally finds her on Bardsey Island, she is shocked by what greets her. According to folklore, the cormorants that fly over the remote Welsh isle are the terrifying witches of Arthurian legend and they are searching for Ivy. Her mum warned her not to come and to stay away from the lighthouse, but now it's too late. As the shadows draw closer, Ivy must look deep within herself if she wants...

Based on the Mabinogion, a collection of medieval Welsh tales, as well as later legends, tells of family members and servants important in the life of King Arthur, featuring Nimue, Morgan le Fay, Luned, and Mordred.

Young mouse Calib Christopher is finally a squire to the Knights of the Round Table, but there is no time to celebrate because his best friend, Cecily, and Merlin's magical treasure are in the clutches of the evil Saxons.