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.

It is a time of celebration on the Worldship, and Knith and her growing circle of family and friends are enjoying the holiday at House Shade. Knith, Aurora, and Caitlyn have to make an appearance at the Capitol celebration, when everything goes awry.

The gifting ceremony is interrupted by a citizen who contracted some sort of alien contagion, and the powers that be find themselves trying to contain the spread of the pathogen while the medical staff, aided by Aurora and Caitlyn, race against time to find a cure.

Then the aliens came...