This epic science fiction saga explores humanity's future after abandoning a ravaged Earth for a new home on the planet Harmony. Here, they are protected by an artificial intelligence known as the Oversoul, which suppresses conflict and dangerous technologies. However, after countless millennia, the Oversoul begins to fail, necessitating a perilous journey back to Earth. Their mission is to find the legendary Keeper of the Earth, the entity that inspired the Oversoul itself, thereby saving humankind from oblivion.
The planet called Harmony had been settled by humans nearly 40 million years before. The colony had been placed under the care of an artificial intelligence, the Oversoul, high in orbit. But now the Oversoul itself is in danger - its systems are failing. By the author of Xenocide.
Feeling itself to be failing, the Oversoul realises that it needs the technology of the Lost Earth to achieve its aims. It has already caused Nafai, a teenage boy, to commit murder ... Nafai, his father and his brothers have left Basilica, but the rest of his family remain there, including his mother, the influential Lady Rasa. However, Rasa has other things on her mind, such as the 'friendly' invasion of troops under the leadership of General Vozmuzhalnoy Vozmozhno of Gorayni, who does not believe in any Gods, including the Oversoul - although he may still be its unknowing instrument.
Above the planet Harmony, the computer Oversoul watches. But its systems are failing and the only hope of repair lies a thousand light-years away on the planet Earth, which was left forty million years ago ... Nafai and his family have been chosen to make the great journey home, but most of them do so grudgingly. Their anger and hatred will make the trek across the desert wastes to the long-abandoned spaceport both harder and more deadly.
The Oversoul of the colony planet Harmony selected the family of Wetchik to carry it back to long-lost Earth. Now grown a tribe in the years of their journey to Harmony's hidden starport, they are ready at last to take a ship to the stars. But from the beginning there has been bitter dispute between Wetchik's sons. The voyage will take decades, during which time the tribe will be held in cold-sleep capsules. But the two factions have different plans, while only the Oversoul holds the key to all their futures.
High above the earth orbits the starship Basilica . On board the huge vessel is a sleeping woman. Of those who made the journey, Shedemai alone has survived the hundred of years since the Children of Wetchik returned to Earth. She now wears the Cloak of the Starmaster, and the Oversoul wakes her sometimes to watch over her descendants on the planet below. The population has grown rapidly--there are cities and nations now, whole peoples descended from the who followed Nafai or Elemak. But in all the long years of watching and searching, the Oversoul has not found the thing it sought. It has not found the Keeper of the Earth, the central intelligence that also can repair the Oversoul's damaged programming.