Corefire (Soulship, #4)

They've become strong enough to hold the ship's darkened halls.
But the night sky can't wait any longer to be saved.
Other powers beyond the Soulship have begun moving, endangering lives even remotely connected to the nigh-extinct starship race. If they are successful, the night sky will become awash in genocide and civil war.
Jasper and Nova must now ensure that enough of the Soulship is safe enough to shelter an evacuated population, and the only way to do so is to advance even deeper into the ancient vessel and activate systems forgotten by even the Soulship herself.
But if they can activate the ship's corefire, then all the monsters roaming between the stars, and all the tyrants seeking to profit in their wake, will finally have something to fear themselves.