Set in the year 2038, the book is a cautionary tale of the harm humans can cause their planet via disregard for the environment and reckless scientific experiments. The book has a large cast of characters and Brin uses them to address a number of environmental issues including endangered species, global warming, refugees from ecological disasters, ecoterrorism, and the social effects of overpopulation. The plot of the book involves an artificially created black hole which has been lost in the Earth's interior and the attempts to recover it before it destroys the planet. The events and revelations which follow reshape humanity and its future in the universe.