Humanity's thousand-year-old interstellar empire has been rotting from the inside for over a century, thanks to venal, corrupt, and power-hungry sovereigns from a dynasty many consider illegitimate. The latest in that lineage, an increasingly psychotic empress, is pushing her realm toward collapse as admirals and generals rebel against her rule. That rebellion quickly drags the once mighty Imperial Fleet into a devastating fratricidal conflict between factions.

One man, Captain Jonas Morane of the cruiser Vanquish, saw the empire's collapse coming years before the first admiral rebelled. When he finds himself the senior surviving officer of a loyalist Navy unit almost entirely annihilated by rebels, Morane puts in motion a plan he developed long ago. However, before his dream can become a reality, Morane must lead the remains of the 197th Imperial Battle Group through an intricate wormhole network and across a shattered empire to the sanctuary he selected, all the while dodging his former colleagues from both sides.

Along the way, he rescues an Imperial Marine Corps Pathfinder battalion and the survivors of a religious order known for its mysticism, and enlists them in his cause. But will Morane's sanctuary survive both the flames of rebellion and the depredations of invading marauders before his rag-tag fleet can reach it?