“Lost Children Archive” begins with an epigraph, a translation of the migrant’s prayer — “To leave is to die a little./To arrive is never to arrive.” Some days, it seems the distances between us cannot be closed. “Lost Children Archive” is a work of fiction that daylights our common humanity and challenges us, as a nation, to reconcile our differences.

In its epic road trip across the disunity of our domestic landscape, Valeria Luiselli’s novel echoes the narrative framework of her nonfiction “Tell Me How It Ends: An Essay in 40 Questions,” in which she drove toward the U.S.-Mexico border with her husband and children.

In both books, Luiselli, a New Yorker born in Mexico City, argues for our country’s responsibility to care for migrant children whose lives and families were made fragile by ruinous federal policies, from the failed war on drugs to destabilizing interventions in the democratic affairs of our southern neighbors.

In spinning “Tell Me How It Ends” into a work of ambitious fiction, Luiselli widens her lens to capture the unruly intimacies of marriage and parenthood.

The unhappy couple at the center of the story — she a radio reporter, he in pursuit of recording more arcane sounds — are no longer tethered by the project that brought them together: to create a soundscape of New York so the languages and ephemera of that great, teeming city will not be erased in its ongoing project to remake itself. Like Luiselli, who translated for refugee children, the narrator involves herself in the immigration proceedings of kids with fraught histories and uncertain futures.

Luiselli nails the joys and discontentments that accumulate in parents who lose sight of their own happiness amid the hustle, the health insurance, the groceries, the laundry. The road trip in “Lost Children Archive” is occasioned by the husband’s move to the Southwest — Apacheria, as he calls it — to capture the echoes of the Chiricahuas led by Geronimo, who is now buried in a cemetery owned by the U.S. Army. Accompanying the husband are the narrator and their children, a boy and a girl produced by prior relationships, marred by knowing their new little family will split up upon arrival.

Despite the layers of pain — the immediate collapse of her marriage set against the brutal deportation of migrant children — the narrator resists self-pity or, as she puts it, becoming someone she would eventually disdain. Every dissolution has two players. “I needed to admit my share: although I hadn’t lit the match that started this fire, for months I had been leaving a trail of dry debris.”

The family drives from one tense roadside exchange to the next amid myriad disintegrations — the couple’s own, and that of our country, both beset by vast, futile ambitions — lightened momentarily by ecstatic splashing in a guitar-shaped motel pool. Throughout, the narrator weaves lyric flashes of Americana in all of its decayed glory — “we see more churches than people, and more signs for places than places themselves” — with kaleidoscopic inquiries into why we, a nation of ragged individuals, exhibit so little compassion for brave kids fleeing death to arrive at our border, bereft but hopeful.

On the heels of the U.S. government’s longest shutdown in history, it bears repeating that though President Trump has made false and racist claims about immigrants to generate public support for a border wall, the inhumane federal treatment of migrant children began before his presidency, which is infamous for forced separations of migrant families.

Under President Barack Obama, the U.S. government fast-tracked the immigration proceedings of unaccompanied migrant Central American children, which sounds like a good thing until Luiselli’s narrator points out — factual references give the novel urgency — that children who could not find a lawyer within 21 days were sent back to the country they escaped.

To build empathy for the lives of children, Luiselli begins with the narrator’s own, safely clicked into their seat belts, air-conditioned in the back seat of a car, sheltered from the violence that drives their brethren north yet exposed to the calamity of parental loss, the confusion of separation and the isolation of diaspora.

Overheard from the narrator’s fixed position in the passenger seat, the children’s word games, derived from listening to adult conversations and audiobooks, recast recent historical atrocities into persistent moral quandaries as they play Apaches and white-eyes, wondering whom they should join, and why.

“Lost Children Archive” unfolds in four parts interspersed with annotated contents of archival boxes belonging to various family members and containing bibliographies, maps, migrant mortality reports, photos and notes.

This archive underpins the narrative, a resonant chamber of books and documents from which Luiselli borrows themes and lines that she reweaves into Elegies for Lost Children, a poetic account of migrant kids braving La Bestia, their perilous traintop journey told in numbered fragments. The narrator and her stepson take turns reading this fictional text by the invented author Ella Camposanto, whose last name means cemetery in Spanish. Lest anyone get upset about artistic license, Luiselli includes a detailed works cited page that sources those quotes, allusions and craft decisions.

Does plot matter, when her deep thinking yields vital insights? Her mind is a delight. Still, Luiselli builds heat she doesn’t use, preferring the elision provided, halfway through, by a switch from the point of view of the wife/mother/narrator to that of her stepson.

Having decided against a dramatic crescendo between the spouses, Luiselli supplants the dull ache of marital grief with something far more panicked. In the book’s late, lyric section, her writing shimmers like its desert setting, flickering among the minds of children walking to find a future. One sentence winds on for 20 pages in a rush of hope that does find its reward.

“Lost Children Archive” concludes with reprints of Polaroids provided by the author, but nominally taken by the fictional stepson, chronicling their family’s journey to the very same canyons where so many peoples have faced their end. Arguing for compassion, again and again, in recurrent narrative parallels, Luiselli refuses to resign herself to a lesser world.

Even now, she writes, children are “traveling alone on trains, crossing the desert, sleeping on the ground under the huge sky.”

Kristen Millares Young is the author of “Subduction,” a novel forthcoming from Red Hen Press on April 14, 2020.

Valeria Luiselli will discuss her book at Politics and Prose on Feb. 19 at 7 p.m.

Lost Children Archive

By Valeria Luiselli

Knopf. 400 pp. $27.95.