The Thea Sisters just finished their finals with perfect scores during the year's final semester. Thea gets a mystery letter from the I.I.S. asking for assistance with a covert mission. Nina, one of their agents, vanished while looking into Ireland. Thea sets off to look for her.
As soon as they learn that the Land of Erin is in peril, the Thea Sisters also decide to embark on the quest. They come across lake fairies, goblins, pixies, and other magical beings as they search for the cause. Some of them fool them while others aid them in their search for the King.
The scene where they take the enchanted elevator to the Land of Erin and return is one of my favorites. It is propelled by a lovely tune that is particular to each nation/mythical region.