In this science fiction epic from Orson Scott Card, it is 40 million years in the future, and humanity long ago abandoned Earth, rendered uninhabitable by their destructive wars. Now, mankind survives on the planet of Harmony, where the Oversoul--an artificial intelligence--protects them from their own worst impulses. There are no wars, no dangerous technologies or weapons of mass destruction.
But after so many millennia, the Oversoul is beginning to fail. Now, a group of humans must return to Earth and seek advice from the entity on which the Oversoul is modeled--the mysterious Keeper of the Earth.