'Astara the Fairy Queen is concerned for her friends the Asrai river fairies. She has gone to visit them in the Diamond River, as she does every mid-winter's night, to have a special dinner and to receive a special gift for her hardest-working fairy, to find they are sick.
'Ziel, the beautiful Asrai Princess, is weak, the fish aren't eating and the ducks have flown away. Even the diamonds have gone missing. Something is causing the river to be polluted and poisoned, and not even Eden s healing cup can help. The fairies soon discover that Garton has been chopping down young green trees in the forest to make his tunnels warm, causing smoke and pollution, and also melting the glaciers where the hobyahs live. The treasure-hungry goblin has also started a mine and taken the wonderful diamonds at the head of the Diamond River.
'The fairies and the hobyahs work together to figure out a way to stop Garton spoiling the environment and making the creatures ill. Ziel draws on her special powers to create wild storms and torrential downpours to fall on the goblins caves, and the hobyahs use a magical ice spell to freeze all the water.
'Meanwhile, the wattleman goes to tell the mistral trees what has happened, who lend the powerful light of their golden flowers to a spell Astara performs to stop the goblins chopping the trees and mining the diamonds.' (Publication summary)