The tribe of the Sun is bound by an ancient law left by long-disappeared Heavenly men: they must not kill. For other tribes that do not have such a law, the people of the Sun are an easy target, unable to defend themselves. Their prey is taken away, stocks are devastated, women are kidnapped and men are killed. When the priestess of the tribe of the Sun Stormy River and her sister are attacked by the Wolf tribe, the River is repulsed and kills the son of their leader. Now that the Wolf Tribe has vowed to exterminate all of its people, the River must do the impossible — prove that it is worthy to be a priestess, and find mythical Heavenly people.