“Free Men,” the new novel by Katy Simpson Smith, takes place in that forest primeval of the American South a few years after the Revolutionary War. In 1788, the United States is still a fragile, new realm, as much claim as country. The British are being sore losers, the Spanish are controlling West Florida and various Indian tribes are shifting their alliances in a fight for survival. But beyond those complicated geopolitical conflicts, the philosophical climate is even stormier. That’s where Smith’s strange, ruminative story develops.

At the heart of the novel lies a backwoods massacre: Traders following Muskogee guides to Pensacola have been robbed and murdered while they slept. One of the party who barely escaped with his life brings word back to his chief that the killers were “a white man, a negro, and an Indian.” The stolen silver is just a cost of trade in these dangerous times, but Chief Seloatka wants the three thieves tracked down and punished.

A dark mystery, a gruesome crime, a relentless chase — “Free Men” holds all those elements, but it largely holds them in abeyance. The action is essentially freeze-framed so that we can see what would have been missed if the plot had galloped past in a fit of murder and retribution.

Each of the criminals speaks to us directly in separate chapters that take us back into their lives before they met one another. Bob, an escaped slave, describes the rising frustration that motivated him to leave his wife and children for a chance at freedom. Cat, a white man, reveals the grueling string of deaths that addled his mind. And Istillicha, the Indian, lays out the internecine plot that finally drove him from his own tribe.

This cycle of monologues is a demanding narrative strategy that requires creating not only distinct ethnic voices but voices from a world more than 200 years before our own. Henry James warned about the challenge of representing what he called “the old consciousness, the soul, the sense, the horizon, the vision of individuals in whose minds half the things that make ours, that make the modern world were non-existent.” To my ear, Smith’s success on this score is uneven. Bob, for instance, is endearing and sympathetic and claims, “I was the ordinariest of slaves,” but his speech frequently rings with a kind of well-educated, modern-day eloquence that sounds anachronistic:

“When I thought about a little person coming into this world who would see things as I saw them, who would crouch in a pen looking at the far fields for a glint of his mother, it grew in my head that this life was not just a single thing, mine alone, but was a big circle that rolled over on itself again and again, that what struck me with pain would strike my child too, that this was not a life but a system, and for the first time my boyish grief took on the color of rage. I didn’t just want my people back; I wanted out.”

That’s hardly the “ordinariest” prose — for an 18th-century slave or even for a contemporary novelist. But the loveliness and stylistic sophistication of such passages inadvertently mute the brutality of slavery with its concomitant conditions of illiteracy and intellectual starvation.

Smith is more convincing when she speaks through Cat, the man ruined by grief. He introduces himself by telling us, “My father was the first woman I knew. His hands split the knots in my hair, folded me on a straw bed, spooned me soup. Belted me, caned me, hided me. He never touched me but to hit me. I was not afraid of him in any way but this. He slept by the day fire and cut sticks at night into beasts. Twisted things, not cows or lambs. Vermin. When he had enough, he’d bury them by the walnut.”

Now that — that blend of innocence and macabre, pocked with weird gaps of logic — sounds entirely believable. As Cat winds through the tragedies that stripped away his happiness and then his sanity, his story resonates with authenticity that makes him seem at once removed from us and linked to us.

But the most captivating voice belongs to a Frenchman named Louis Le Clerc Milfort, who works as a tracker and freelance deputy of justice. He’s abandoned a spoiled marriage in France and, like a woodland de Tocqueville, he’s come to America “to catalog the divergences of man” in this brave new world, a place free from the fetid strictures of the past. “I left friends behind in Paris who dissect amphibians and sketch leaves,” he says, “but I hope to earn my place in the burgeoning science by classifying human action, to construct not a hierarchy but rather a forecast for future generations.” When he hears of the robbery-murder, he volunteers to track down the criminals for the Muskogee chief, but he has a larger interest. How, he wonders, “did a white man meet a black man meet an Indian?” To him, this odd trio represents “a rare encapsulation of the types of man, a scale model of American brutality and independence.”

Le Clerc’s search feels at once like a project of 18th century anthropology and a timeless reflection on our national character. As he pursues these three guilt-ridden murderers, he’s determined “to prove that there was a sublayer to humanity that was common across the classes, and that no matter the station one was born to, some universal concern made one recognizable as a man as opposed to any other beast.” But that quasi-scientific interest — “hunting the human temperament,” as he says — makes Le Clerc reluctant to capture these men and thereby bring his clandestine observations to an end. “In any country in the world they could not subject together, yet here they were, wandering in a polite clump through woods that belonged apparently to no one, ignoring all the reasons to strike out on their own, to take the money and fall back into their segregated homes.”

In these hypnotic pages, Le Clerc’s obsession becomes our obsession. “I trail them, every hour less like a pursuer and more like a pilgrim,” he says. “I can no longer justify my delay in seizing them unless I admit to myself that here before me is everything I once believed to be a dream.” What new species of friendship binds these three unlikely murderers? What inspires their dangerous devotion to each other?

“There is something of America in all this,” Le Clerc says half in frustration, half in awe. And he’s right. With this collage of experiences twisted together and soaked in blood, Smith cuts to the bone of our national character. Then, as now, for all its violence and desperation, it’s noble and inspiring, too.