When refugees from a war-ravaged Earth first settled Harmony, they built a master computer as a guardian of the peace-a machine designed to keep people from developing the technology that devastated their old world. Their descendants, genetically altered to receive the computer's transmissions, worshiped its voice within-what they called the Oversoul. But after 40 million years, the Oversoul began breaking down. To be repaired, its core had to interface with the even more powerful master computer still on Earth.