Cinnabar Shadows

While the Dark Sun campaign setting wasn't wildly popular, I've always enjoyed the books that are set in it. Athas was devastaged in the past by the rule of the Dragon, and the magic of the defilers, that obtain their power by sucking the life out of plants and animals around them. This has caused the vast desert of that is the setting for these books. In this one, a rabid 'environmentalist' halfling has a plan to fix the problem once and for all, and an unlikely group of 'heroes' must stop him. Its a little incomplete in some ways, but still good. Lynn Abbey wrote the first book and the 4th book in the series, this is book 4. It seems like there was an intention to have more, but I don't know of any more in the series.

Water. On Athas, it is life, it is currency, it is power... The watery caverns beneath Urik have become a haven for political refugees and runaway slaves, a place safe from the ravages of Athas and her defilers. Until one such defiler brings destruction to the haven. Mahtra, who fled sunlit Urik for the dark undercity, must now emerge to set all to right. Her quest leads her to the palace of a sorcerer-king, to an ancient druidic grove, and beyond...