Wolf-Speaker - Tamora Pierce

Daine's magic must save her friends--both wolf and human--in this second book of the Immortals series, featuring an updated cover for longtime fans and fresh converts alike, and including an all-new afterword from Tamora Pierce.
When Daine is summoned to help a pack of wolves--dear friends from her old village--she and Numair travel to Dunlath Valley to answer the call. But when they arrive, Daine is shocked to learn that it's not only animals whose lives are threatened; people are in danger, too.
Dunlath's rulers have discovered black opals in their valley. They're dead set on mining the opals and using the magic contained in the stones to overthrow King Jonathan. Even if it means irreversibly damaging the land--and killing their workers. Daine must master her wild magic in order to save both her animal friends and her human ones.