From the inside flap:
"A small group of humans has survived the apocalyptic epidemic called Black Ep, a disease that ravaged the world and left them alone on Earth. The survivors gradually awaken others, who have been put into a state of frozen sleep to await a future when disease might be cured. At first, everyone agrees on the basics: We're lucky to be alive. We're all in this together. Let's look out for each other and build a better world.
"But inevitably, as more sleepers are roused, there are those who disagree. People who remember power are waking up to a new world, and they do not intend to wait their turn politely. And from very far off indeed, one more surprise awaits the survivors -- a shock that will transform the future for everyone in this post-plague, perhaps even post-human, world."
A few years after the happenings of Edenborn, the six surviving post-humans (Vashti, Champagne, Isaac, Pandora, Halloween and the largely-absent Fantasia) are still working to revive the cryogenic human sleepers (dubbed "Popsicles" by the post-humans) and create a society for the humans that will evolve into a more permanently-structured society -- a society that humans run, without too much help from the post-humans.
Inevitably, there are attempted coups and political factionings by the humans, and other threats -- crazy and unforseen -- that threaten the tremulous balance of this uncertain new world.
Everfree is as humorous, exciting and unputdownable as Sagan's two previous books, Idlewild and Edenborn, evolving the characters, and wrapping up pertinent plot points, while leaving room for future ones -- much like life itself, if one views life as a story.
Stunning series, this. Check it out.