The Guardians of the underground land of Nainya have watched over the desolate people on the surface for years, protecting them against evil. But war is brewing in the barren wastes of Hymbroli, and Katarna, the only Guardian who can stop the advance of the enemy, has vanished into the desolate land. It is up to Myst, her sister, to seek out the missing Guardian. Myst and her companions, Shadow, Boar and Wanderer, find themselves in a desperate race to reach Katarna before the enemy - but with the Guardians themselves torn between darkness and light, and their foes attacking at every turn, can they do it?