Glinda the Good was one of the most powerful sorcerors in all the known spheres (as well as most of the unknown ones). She ruled the southern land of the Quadlings with grace and compassion (and a well disciplined army of female warriors). For over a century she served Ozma and protected Oz from a bewildering array of threats and invasions.
But Glinda has vanished. Vanished so thoroughly that the most powerful magics in Oz have been unable to find her.