After Young elf Cuchulainn is tricked and attacked, he discovers the Golden Torc, the seal of power of Niamh Queen of the fairies, has been stolen. It is believed the queen's sister Dierdie, a sorceress of the Black Art is behind the theft, and the Golden Torc is hidden in the Castle of Dunluce, protected by a Banshee. With the help of others, Jennifer and Cuchulainn attempt retrieve the Torc, having to outwit both the Castle's formidable defences and the Banshee. But, even if they are successful, a great battle is brewing. And the outcome of the battle could spell the end for the elves and fairies of Glenarrif forest.