Only a few weeks ago, Meg Morgan and her siblings went to England for the holidays and found themselves in the middle of a fairy war. Now the war is over, but the battle for control of the fairies has just begun.A mysterious painter named Gwidion appears at the Rookery, ready to give the children art lessons. But his real plans are far more sinister: He means to destroy the Guardian of the Green Hill, the woman who keeps the peace between fairies...