In a hot and gritty city populated by super-intelligent robots called 'Hums', May seeks some reprieve from recent hardships and from her family's addiction to their devices. She splurges on a weekend away at the Botanical Garden - a rare, green refuge in the heart of the city, where forests, streams and animals flourish. But when it becomes clear that the Garden is not the idyll she hoped it would be, and her children come under threat, May is forced to put her trust in a Hum of uncertain motives in order to restore the life of her family.