Empire of Light: Shoal, Book 3

In the third Shoal book, the nova war has begun to spread as the Emissaries force the Shoal into a desperate retreat. While Dakota goes in search of the entity responsible for creating the Maker caches, Corso, left in charge of a fleet of Magi ships, finds his authority crumbling in the face of politically-motivated sabotage. If any hope exists at all, it lies in an abandoned asteroid a thousand light-years away, and with Ty Whitecloud, the only man alive who can decipher messages left behind by an ancient starfaring race. Unfortunately Whitecloud is imprisoned aboard a coreship adrift in space, awaiting execution for war crimes. But if humanity has any hope of survival, Corso is going to have to find some way to keep him alive - and that's only if Dakota doesn't kill him first.