The River is dying. Seven years have passed with no rain, no melting snow, and no reason why. Then Arxes, crown prince of an unimportant middling kingdom, sees in a dry canal a spring, where a maiden wades, wearing a crown of jewel-blue flowers. The kingdom's soothsayer deems it an omen, revealing the drought's cause is magic, with its only solution at the River's mysterious Source. Arxes finds himself declared Quester, his sole advice for the journey, "Only set out!"

On the road, Arxes and his staunch comrade Ervan will track the River through desert, forest, city and steppe, encountering an emperor, an enchantress, a shaman, a witch. They will meet unforeseen friends and foes, gods, monsters, beings out of myth; they will risk the elemental perils of lightning, fire and ice. And before the River can flow again, the last in a long line of crucial decisions will bring the hardest choice of Arxes' life.