Magic's Price (The Last Herald-Mage Series, Book 3)

The final chapter in Mercedes Lackey's spellbinding fantasy trilogy! The Herald-Mage, Vanyel, and his Companion, Yfandes, are alone responsible for saving the once-peaceful kingdom of Valdemar from the forces of a master who wields a dark, forbidding magic. And if either Vanyel or Yfandes falters, both Valdemar and its Herald-Mage must pay the ultimate price.