In the magical kingdom of Orkena, a teenaged girl is chosen to be the human sacrifice in a deadly game between three heirs who will do anything for the crown. Zahru has dreamed having adventures, but as a lowly Whisperer in the kingdom of Orkena, her power to commune with animals means that her place is serving in the royal stables until the day her magic runs dry. Then the ailing ruler invokes the Crossing: a death-defying race across the desert, in which the first of his heirs to finish-- and take the life of a human sacrifice at the journey's end-- will ascend to the throne and be granted unparalleled abilities. When a minor indiscretion turns into a deadly mistake, Zahru is caught up in a feud between the heirs and will become the Crossing's human sacrifice-- unless she figures out how to overcome the most dangerous people in the world. -- adapted from jacket

Series information from Goodreads.