It is 2084. Climate change has made life on the Caribbean island of Bajacu a gruelling trial. The sun is so hot that people must sleep in the day and live and work at night. In a world of desperate scarcity, people who reach forty are expendable. Those who still survive in the cities and towns are ruled over by the brutal, fascistic Domins, and the order has gone out for another evacuation to less sea-threatened parts of the capital. ​Sorrel can take no more and she persuades her mother, Bibi, that they should flee the city and head for higher ground in the interior. She has heard there are groups known as Tribals, bitter enemies of the Domins, who have found ways of surviving in the hills, but she also knows they will have to evade the packs of ferals, animals with a taste for human flesh. Not least she knows that the sun will kill them if they can’t find shelter.