The posthumans have a plan for humanity's future, which they call The Doctrine. It simply states that the world is a collective—that we're all in this together. The world is nearly empty, and there's plenty of everything to go around for everyone. The old way of doing things doesn't need to continue.

But since only the most fortunate could afford to be frozen, the human survivors of Black Ep are mostly CEOs and other wealthy businessmen or politicians—not exactly the sort of people who would be willing to agree to a new world order without their having something to say about it. And they certainly don't appreciate having to do menial (by their standards) jobs, while the posthumans are seemingly above it all, running things.

Protagonist Gabriel Hall, or Hal (short for Halloween), as he prefers to be called, didn't want to thaw out the cryopreserved in the first place, but his fellow posthumans—Vashti, Isaac, Pandora and Champagne—outvoted him four to one. He thought about running off to some isolated corner of the world again (as he did at the end of Idlewild), to leave reconstruction to his compatriots, but this time his love for Pandora convinces him to stick around Victory City to help rebuild civilization.

There, he serves as chief of security. Though there are only a few thousand humans revived, he has his hands full keeping track of potential "bad apples"—former Popsicles who don't like their new place in society. Eventually, these malcontents organize and overthrow the posthumans' peaceful government, forcing Hal to take drastic action in response.

Meanwhile, a new virus seems to be spreading rapidly throughout the population. Is it something new, something different? Or could it be a new strain of Black Ep coming back to destroy a revived human race? Or will the human race simply destroy itself?

A bleak future from a writer with a bright one

Readers new to Nick Sagan's work probably have some lofty expectations. His father, the world-renowned Carl Sagan, was both a brilliant scientist and the author of many books, including the terrific SF novel Contact. So he clearly has the genes for good writing and smart science; the question is, does he live up to expectations? The answer is yes and then some, and luckily for SF fans, the younger Sagan has his father's gift for storytelling, but has chosen to devote his life not to writing science but to writing science fiction.

With post-apocalyptic SF dating all the way back to Mary Shelley's The Last Man (1826), and with such indisputable classics as A Canticle for Leibowitz and Earth Abides residing within its ranks, any new novel that treads in that same territory has to work twice as hard to come off as fresh and not derivative. So it's quite a trick that Sagan pulls in making Everfree (and its predecessors) not only a fun and entertaining read, but also a startlingly original take on the subgenre. Sagan eradicates the human population like no other novel or series in recent memory and rebuilds the world in a conceivable and inventive way.

The SF ideas here—and there are plenty of them—are all very cool, especially the "applesauce" strategy that Hal employs at the end of part two. But it's really the characters that make Everfree special. Hal and his compatriots may be posthuman, but they display an innate humanness that really resonates beyond these pages. Their interpersonal relationships are complex and dynamic, grounding the novel in reality even as its bleak future setting seems so foreign (yet all too plausible). Sagan leaves the characters no easy options, and so the narrative is fraught with moral dilemmas and conflict.

Hal has always been the star of this series, and the action unfolds mainly from the his cynical point of view, which is a welcome return after his frustrating background role in Edenborn. Sections one and three are all Hal, while section two splits the narrative between Hal, Isaac, Fantasia and Sloane. Fantasia's dementia is intriguing, but her train of thought is a bit disjointed. Isaac and Sloane, meanwhile, both so very different from Hal, offer some interesting insights, but this middle section is the weakest in the novel, the only place that it really bogs down at all. Still, there's plenty of action and plot advancement in this section, rendering this complaint a minor one.

Although the characters engage in some morally questionable actions as the end of the novel draws near, the narrative still manages to end on a note that resonates with hope, and the final chapters fly by, leading up to a denouement that brings the series to an undeniably satisfying and triumphant conclusion.