The Exodus — Bryan Thomas Schmidt

The concluding volume in Bryan Thomas Schmidt's epic space opera trilogy The tyrant Xalivar is dead, and yet the Vertullians are weary of the persecution against their people. They have decided to leave the Borali System and start over somewhere else. But the attacks begin again, first by space pirates, and then by something more. When large numbers of officers from the Borali Alliance military disappear, High Lord Councilor Tarkanius is forced to ally with Davi Rhii and the Vertullian leaders. Once again, they have to face a threat that might destroy them all. Can ancient enemies ever live in peace?