McCaughrean writes with such richness and builds worlds with such expertise you can see the scenes of desperation, smell the sweat from the workers manning the water pumps. The story jumps between the city and the North where a boy called Clem Woolen loses his home and is temporarily separated from his dog Heinz, and we see the impact of Suprema’s carelessness. As so often with dual narratives, one grips more than the other; in the first half I was always keen to return to Praesto. McCaughrean makes important points about climate change, but I found her constant evisceration of newspapers as receptacles of fake news a little wearing (the story is peppered with bogus reports).