Tales are told of the mysterious, powerful Mountain where the gods–powerful beings in the form of white horses–live. But Valeria knows no woman has ever been called to the Mountain. Until she feels a strange pull and answers the call–as a boy.... When her secret is discovered Valeria loses all that she's won. Her anger and frustration with the Empire might be enough to give the barbarians a way into the Mountain. And so the Empire now depends on the will, the strength and the loyalty of one Rider. A Rider who has been rejected by all but the gods...