Ash, from the Last Village, is forced to leave his home when the water supply dries up and the other villagers vanish without trace. In a world that seems to be slowing burning in the ever-increasing heat, water is humanity’s most precious resource – and it’s running out.
The dystopian setting considers the consequences of failures to act to arrest climate change. It shows how different communities have responded: Ash's village is in a thrall to a belief system which elicits social control through a narrative of acceptance of current suffering to appease the gods, while Bronwyn's village’s ethos of trust no one is evident from its architecture: all dwellings are spaced far apart from each other.
Whether the priestess of Ash's village genuinely believed herself to be in communion with their ancestors or was a charlatan who extracted advantages for herself from this perception is not made clear, but Spark does illustrate how a powerful elite can annexe precious resources for itself (in this case, water), to the disadvantage and peril of those without power. It also explores the exploitation of human labour dependent on systems of spying and informing.
The book is a muted and affecting exposé of how organised religion can prolong and justify human suffering, where human inaction is in fact harmful, and it is only human compassion that establishes bonds and defeats tyranny.