When Sabrina finds a leprechaun named Finicky Fergus in her kitchen, a joking remark leaves her in big trouble. Fergus flies into a rage and vows to plague Sabrina with pranks until she learns some respect - or until she does him a fovour. And what is the favour? She has to steal the King of the Leprechauns' gold which is stashed at the end of the rainbow. Meanwhile Harvy, Libby and Mr Kraft eat Aunt Hilda's special shamrock cookies which allow mortals on St Patrick's Day to see Leprechauns and they soon decide to go to the end of the rainbow just to see what is there! Well this all sounds like a recipe for disaster - and it is! To reach the end of the rainbow, they have to by-pass several legendary Celtic heroes. Can Sabrina and her friends make it to the pot of gold - and back to the mortal realm?