After her favorite mare dies while giving birth on her grandfather's farm, Polly's spirits are lifted when she discovers that the foal is a magical baby unicorn. The secret spreads throughout the village, and troublemakers finagle to steal the unicorn for their own gains.

Every hundred years, the evil sorceress Morgana returns to claim Fingall's talisman from Merlin, with which she intends to destroy the world. For the last fourteen hundred years she has failed... now she intends to conquer all. Young Ben Clark moves with his parents to a new town, where he befriends his elderly magician neighbor, Milner. Ben has a natural talent for magic and wants to learn all that he can from this old man. Ben carries the same scar as the original staff-bearer 1,400 years before. Both Morgana and Milner, who is revealed to be Merlin, see this as a sign that this time, the battle between good and evil will be stronger and harder than ever. Ben must make his own choice between good and evil as he is drawn into a battle and must draw on his own spirit and magic to decide which path to follow and hence, the fate of the world as we know it.

When Merlin cast a positive spell to protect the knights of the Round Table, he used ancient magic drawing on the power of Stonehenge, and the knights were put into a sort of suspended animation. The evil Morgana and her son Mordred were banished into another world for 1500 years, but a 20th-century scientist finds a gateway, and the dark lord has a vicious scheme to enslave King Arthur's world.

When Kyle and Evie Preston start exploring the grounds of their late grandmother's house they discover an old, abandoned mine shaft and soon find that the old lady's stories about fairies trapped underground were true.

Kari Wührer stars as a witch, who turns the king's son Barek into an immortal berserker. The enmity between Barek and the witch extends to the present day in his attempts to become mortal again and break Odin's curse.