Three generations ago, the world collapsed in an eco-catastrophe — a collapse brought on by overpopulation and violence. The survivors’ descendants inherited a poisoned world. Those few who eke out an existence have no memory of the glory days, no knowledge of a world rich in people, technology, and wildlife. But the dead remember . . . Before the collapse, people were downloading their minds into solar-powered gravestones. Most of them endure. Some are even sane. And in a world where darkness and ignorance have enveloped everything and everyone, these sentient tombstones may be mankind’s only hope for survival. . . .