Perched on a sloping hill, set away from a small town by the sea, the High House has a tide pool and a mill, a vegetable garden, and, most importantly, a barn full of supplies. Caro, Pauly, Sally, and Grandy are safe, so far, from the rising water that threatens to destroy the town and that has, perhaps, already destroyed everything else. But for how long? Caro and her younger half-brother, Pauly, arrive at the High House after her father and stepmother fall victim to a faraway climate disaster -- but not before they call and urge Caro to leave London. In their new home, a converted summer house cared for by Grandy and his granddaughter, Sally, the two pairs learn to live together. Yet there are limits to their safety, limits to the supplies, limits to what Grandy -- the former village caretaker, a man who knows how to do everything -- can teach them as his health fails.