In the years 2300, mankind launched a disastrous attempt to diversify the human race by genetic engineering and sow it across the universe as multiple settlements of different subspecies. Three hundred years later, the textbooks teach that the Diversification Project failed. Like most of the people of her generation, young graduate student Sandra Lynn believes that there is no life beyond earth, not any more. The viruses used to change human DNA mutated more rapidly than the genetically engineered people that were created. The result was interplanetary plagues that destroyed nearly all life. Now, only a few select people travel space, setting up automated mining operations and sterilizing the ruins of the old Diversification cities and settlements. Anyway, that's the official story. But for Sandra Lynn, a mere language historian and mythologist, the sudden intrusion into her life by one of these celebrity space pilots upends her quiet life. Sir George Stewart wants to know if there is such a thing as ghosts. What has he found while rambling through the dead planets beyond the solar system? And what has he brought back with him? An invitation to his remote winter estate opens the door to an unexpectedly living and dangerous universe.