The witches from the Volcano of Gloom have devised a way to steal the Flutter Ponies' Sunstone. Without the Sunstone, Flutter Valley will wither and die! The witches have enlisted the help of Queen Bumble and the bees from Bumleland, who also hate the Flutter Ponies, to steal the Sunstone and take it to Bumbleland where it will help flowers grow so they have all the nectar they need. The witches in turn will get Flutter Valley, which will be dark and gloomy without the heat of the Sunstone. (thetvdb.com)