The Obsidian Society

To turn within is to survive.
After the collapse of humanity in 2211, Lettie Valentine, her family, and the rest of Washington D.C.'s Black upper class sought refuge in the ruins of Salt Lake City. As the Founders of the Obsidian Society, they turned inward, protecting their own against the remaining Colonies on Earth.
Now, after years of hard-won peace and growth under the Valentines' helm, cracks begin to surface. Their father, the colony's predecessor, is gone, and Lettie's older brother conspires against their mother for power. Waves of hostile Colonists suddenly bombard their home, seemingly steered by the mysterious Renewed Citizen's Front, who fled the galaxy over a decade ago.
But when the Front returns to Earth under a banner of peace, Lettie is no longer able to alleviate her community's rifts, especially when her growing attraction to one of its emissaries causes her allegiances to waver. New bonds and unexpected leadership find Lettie turning outward in search of the answer to saving Salt Lake, at a cost.