Vast

Aboard Null Boundary, a giant starship thousands of years old, four survivors of an ancient alien war are making a desperate journey: Lot, son of a fiery prophet and carrier of an insidious virus that spreads a cultlike religious mania among those it infects; Urban, Lot's boyhood friend from the city of Silk, and a man in search of challenge and adventure; Clemantine, cast adrift when her world was destroyed, and yearning for revenge; and Nikko, sometimes a living man, but always the ship's disembodied mind.
They are bound for unknown territory. Ahead of them loom vast, lightless clouds of dust and gas where stars are born, and where the alien Chenzeme are believed to live. The Chenzeme are an enigmatic race whose automated warships have ravaged the living worlds of the galaxy's Orion arm for millions of years. But why? Null Boundary's crew is driven to find out--though in their quest to discover the source of the Chenzeme, they must also explore the terrible truth of their own past, the meaning of revenge, and the price each one of them is willing to pay for survival.