Flight of the King - C. R. Grey

When animals and humans unite, amazing things can happen. Bailey and his group of friends are back at Fairmount academy, accompanied by Gwen, the Elder's apprentice. But all is not well. They quickly figure out that evil ruler Viviana has something planned for the day of her grand Progress Fair, and knowing Viviana, it won't be good. But their plans to stop her are swiftly torn apart. Taleth, the last white tiger and Bailey's only kin, is kidnapped. Bailey and Hal must follow her trail deep into the Dust Plains, but they could never have predicted the danger that they will find there. Meanwhile, Gwen and Phi are on a quest of their own - having been entrusted with finding 'The Instrument of Change', they know their mission is an important one. But could Gwen be more special than she knows? Somehow, although they are separated, the friends must pull together. Because the fate of not just the kingdom, but the Animas bond itself, is in their hands...