The Survivors — Marion Zimmer Bradley

Asked to investigate a Closed World, Dane, Rianne, and Aratak begin their mission but are interrupted when the uneasy peace between coexisting sentient races is threatened by ghosts and dragons.

Dane, Rianna and the monster Aratak…they were the survivors of the terrible hunt of the Red Moon. Where all others had failed, they had lived -- to achieve fame and fortune and to find life in the starways unexpectedly colorless -- until they were asked to check out a Closed World.

To the combined intelligences, a Closed World was one that held a mystery science had not cracked, and thereby held danger. Because the Survivors had become over-confident of their abilities, they took the challenge.

But they had not counted on the problem of the only known world with two dominant ruling species living in precarious harmony -- and with the dread ghosts of white dragons that seemed bent on shattering that harmony.