Jonah, who suffers from scoliosis and epileptic seizures, worries that he will lose his best friend when she has a premonition warning her to leave town.
In 2250, water is scarce and controlled by tyrants, but when sixteen-year-old Luca descends to the domain of the Water Rats, he meets one who captures his heart and leads him to secrets about a vast conspiracy, and about himself.