Edenborn (Idlewild Trilogy 2)

Edenborn begins with a stark landscape-a microbial apocalypse called Black Ep has wiped humanity from the globe-yet all is not lost. Six individuals have survived the epidemic and are now committed to the task of rebuilding a peaceful civilization. But not everyone shares the same vision, and soon two very different societies begin to form. As we follow a child from each "family," someone-or something-begins to threaten their innocence. And as the mystery mounts, a mutated strain of Black Ep makes a deadly return. Now the architects who gave breath to this new world must scramble to protect their children from a two-front assault. It's a race against extinction, and Nick Sagan keeps us riveted to the page.