The once fertile soil has been poisoned, a ''Grand Contagion'' has decimated the population, highways and factories lie in ruins, and barbarians on horseback roam the hills of what ''used to be America,'' raping and killing. No wonder the land is emptying out, as emigrants stream eastward hoping for a better life...in Europe. Just when you've shaken off the ash from Cormac McCarthy's The Road, along comes The Pesthouse by Jim Crace, another grim and vivid postapocalyptic fantasia.
The Pesthouse of the title is America itself, but it is also an actual pesthouse, a quarantine hut just outside a river town where Margaret, a beautiful young woman, is sent to die. After coming down with the plague-like ''flux,'' her hair is shorn so she can be easily identified and avoided, and her family abandons her to a lonely deathbed. But Margaret survives, nursed to health by Franklin, a sweet-natured emigrant who stumbles upon the pesthouse while seeking shelter from a storm. Risking contagion, he rubs her feet and whispers to her of his hopes for the future in Europe, ''sure that life would be more prosperous. How could it not be better there? Safer too. With opportunity, a word he'd come to love.''
Yes, even with their society in shambles, these latter-day Americans are as recklessly drunk on opportunity as their forebears, eager to forsake the disappointing world they know for some distant, intangible opportunity. Restored to strength, Margaret and Franklin make their way east, contending with flamboyantly hateful kidnappers (who braid ribbons in their filthy beards), torrential rivers, a freakish religious cult, and their single-minded, sadly deluded fellow travelers. It's a little too hammy to be thoroughly convincing, but it's a cracking adventure story. And Crace pulls off a transcendent ending that offers both a biting comment on the ongoing American experiment and one possible finale. B+