The Firestone: Book One of the Sorcet Chronicles
by Stephen Morrill
On the world of Tessene, Tachi and Caitlin, two young humans from Earth, serve as taidar to Sorcet, a deru of the Gray Guild who conducts dangerous missions for the Gray Guild library and is determined to close the world portals. Taidar are expected to die for or at the command of their deru. They succeed in closing the Firestone Portal . . . but only one taidar remains.