Post-apocalyptic novels are supposed to be bleak, but Jesus! Jeff Carlson's Plague trilogy is shaping up to be the grimmest and most intense end of the world epic SF has seen in many a moon. Depending on your tastes, it can be just too hard to take after a while. Carlson's heroes — nanotech researcher Ruth Goldman and her companion Cam Najarro — endure hardships and setbacks nearly too brutal for words. If most of us were in their shoes, we'd probably sit down by the nearest tree and decide there was just no point in getting up again. It isn't enough that a ghastly nanotech virus has been unleashed upon the world so devastating that it might as well qualify as an extinction event. Now Ruth and Cam find themselves just about the only people in possession of an effective vaccine against the scourge. But the very people whom they should be able to trust, the tattered remnants of the US government, holed up on a Colorado mountaintop, are more interested in weaponizing new strains of nano, to fend off the imminent invasions from China and Russia, as well as a growing rebel movement that threatens a whole new American civil war to boot.

I was reluctant to see a sequel to Plague Year, but Carlson has reinforced what I admired about him in that book: that he's perfectly willing to resist any (and I do mean any) recourse to cheap sentiment in favor of conveying his story and themes with as much authenticity and emotional truth as possible. Thus even the scenes in Plague War where lesser storytellers would find it easy to cave in to button-mashing, such as the way Carlson has Cam and Ruth deal with their complex and conflicted feelings towards one another, are just as relentlessly honest as its numerous scenes of destruction. Personal needs — even those as basic and grounding as love — always take a back seat to duty and the greater good here, even if the sacrifice would be, at any other time, too painful to bear. Ruth is constantly wracked by guilt, even when she has no good reason to feel that way. Knowing she possesses the knowledge to combat the plague, but unable for over half the book to find herself in a position to do so, fills her with feelings of self-recrimination that she must be doing more. And when others sacrifice themselves to help her achieve those ends, it simply adds to the anguish.

Is all of this sounding, well, monumentally heavy? That's because it is. Which prompts the question of just how far a writer ought to go when writing about the end of the world as we know it. It seems to me there really isn't an honest approach other than to take the concept to its logical end — which means you aren't going to feel fine. For about the first half of the the book, Cam, Ruth, and a soldier named Newcombe who aided the two of them in the theft of the nano vaccine at the end of the previous book, simply trudge across the desolated Californian landscape. The scenes don't have the poetic loneliness of, say, Cormac McCarthy's The Road, but rather a stomach-knotting sense that survival, literally hour by hour, in this post-plague world, is a Sisyphean effort. Food is limited, water is dangerous, bugs have bred so wildly that even encountering an ant colony could mean a ghasty horror-movie death, and to top it all off, they're being hunted by the patchwork government operating out of Leadville, Colorado. There is simply nothing to do but keep moving and keep hiding, all the while looking for whatever remnants of survivors may still be clustered on high ground, above the 10,000 ft. elevation threshold beyond which the nano cannot function.

Perhaps the only concession Carlson makes to cliché are some of the Leadville characters: the de rigeur dastardly hawkish senator who raises cynicism to the level of performance art by treating the end of humanity as a chance at power. But there is a hint that even he is someone who's responding to the crisis in the only way his experience and ideology has conditioned him to, that's he truly convinced his methods are the best.

Though Ruth centers the story as the heroine we're meant to root for, Carlson is careful not to flood the book with simplistic villains for us to hate. Even among the good guys, loyalties can be a fragile thing, not because of mendacity on anyone's part, but because the situation they're all trying to survive is such a chaotic nightmare that it's often too confusing to know what the right choice might be. There are simply no easy decisions here, no instance where Ruth can simply put her finger on the solution that will make most everyone happy, or have the best possible benefit with the least cost. Whatever she decides, she stands to lose somebody, or worse, some greater part of herself.

Ultimately I'd have to say that Plague War may be too good at what it does for its own good. It isn't a book without hope, by any means. The fact that Ruth and Cam keep going far past the point when all seems lost, and then keep going some more, is testament to that. But the whole affair will probably prove too difficult for a lot of readers to endure. And the story does go through patches where it feels monotonous in its unrelenting gloom. I waffled on the 3½ to 4-star split before deciding to go conservative. Unlike Plague Year, which moved like lightning half the time and played more like a technothriller — punctuated by the occasional adrenalizing and cinematic action scene, like the space shuttle crash landing or the pulse-pounding climactic shootout and chase through the ruins of Sacramento — the tone of Plague War is that of a character-centered survival drama. Its pacing is far more deliberate, with significantly less action. I did think it was a good choice to have the war happening in the background for much of the book, as it conveyed the anxiety of the characters, wandering lost and desperate with no way to get news of what's going on just over the horizon, with chilling immediacy. But this is an unforgiving and dark piece of storytelling indeed. Yes, I think that's what good cautionary storytelling ought to be. Just consider yourself warned. This one is a literary level-four hot zone.