When the Earth is threatened by a slowly expanding sun, mankind embarks upon a mission to send a mammoth Worldship to settle a new planet across the stars. The preternatural races step out of hiding to work with the humans to save what they can from their dying world. With the aid of the Fae, shape shifters, Vampires, and other creatures of supernatural lore, the Worldship, Leviathan, is complete one thousand years later.

The one thing about interstellar space is that it is vast on a scale that is almost incomprehensible. Yet the Worlsdhip Leviathan finds that there are two herculean vessels approaching on an intercept course from the Earth they left behind five thousand years ago.

Conditions are dire on the Cityships, and an advance team is sent to evaluate the ships and the people on board. Knith Shade, Brigade Enforcer is put in charge of the humanitarian mission.

Upon the conclusion of the mission, Knith finds herself and the very world itself, fighting for their lives in a battle that will decide the fate of the twelve million souls aboard the Leviathan.