Kawakami explores the evolving definition of humanity in a world where traditional reproduction is rare. Children are created in labs, some drawing sustenance like plants from water and light, while others are hybrids, carrying the genetic legacy of both humans and animals.

The ever-present shadow of extinction looms large throughout the narrative, serving as a stark reminder of the fragility of life and the delicate balance of ecosystems. The novel portrays the struggle for survival, both physically and in preserving memories, culture, and human essence.

Despite the bleak backdrop of a dying world, Kawakami weaves a powerful narrative about the enduring strength of human connection. Through interconnected episodes, she explores the complexities of love, friendship, and familial bonds in this strange new world.