“We have a ghost in here.” That’s how Toni Morrison writes in “Beloved” about the spiteful specter that haunts an old house in Cincinnati.

Her artful invocation of that ghost remains incomparable but also widely relevant to the history of African Americans in this country. The spiritual practices that kidnapped Africans carried with them to the United States affirmed the immanent presence of their ancestors. The trauma of the Civil War inflamed white Americans’ interest in spiritualism. And Klansmen materialized the evil forces of racism as white-robed phantoms.

We have all kinds of ghosts in here.

Margaret Wilkerson Sexton takes on this legacy in her new novel, “The Revisioners.” Spanning more than 160 years, the story begins in present-day New Orleans and immediately questions the presumptions of our self-satisfied social progress.

The narrator, Ava, is a biracial single mother trained as a paralegal but between jobs. Determined to save money, she accepts an invitation from her white grandmother to work as a companion.

Although their arrangement seems mutually convenient, it’s fraught with unacknowledged tensions beyond the usual ones involved with caring for an older relative.

Ava’s grandmother is a wealthy woman used to being waited on. In her confused moments, her mind slips back to an era much more openly racist. She’s a troubling emblem of a nation determined to be gracious and think the best of itself but still capable of shocking outbursts of hatred.

For her part, Ava underestimates the pernicious influence of this setting: The grand house and everything about the way it functions silently confirm the hierarchy of employers and servants, whites and blacks. Ava’s blurry position as paid help and loving relative leaves plenty of room for hurt feelings to fester.

Sexton explores these unspoken tensions brilliantly. Her subtle portrayal of a black mother’s competing desires is layered with both pathos and wit. Ava wants her teenage son to be happy living with Grandma, but she doesn’t “want him to become all golly gee” like Carlton from “The Fresh Prince of Bel-Air.” She wants him to enjoy the fancy new school, but she’s wary of the skinny white mothers who wear their enthusiasm for diversity like a badge of honor.

As Ava negotiates these racial complications of modern life, she takes comfort in the memory of her great-great-grandmother, a woman named Josephine who survived slavery and went on to own her own farm. We hear from her as an enslaved child in 1855 and as a successful businesswoman in 1924. That structure is complex, but Sexton writes with such a clear sense of place and time that each of these intermingled stories feels essential and dramatic in its own way.

In the most distant storyline, young Josephine is a girl caught in the dehumanizing demands of plantation life. She’s assigned to be a companion to the master’s daughter, a job that mimics the outlines of friendship within a system of rape, torture and murder. Outside the master’s house, Josephine is introduced to the spiritual work of the Revisioners, a subversive group of slaves who pray and sing and even foresee the future.

That life-or-death drama on the plantation provides the novel’s most terrifying moments, which could easily have rendered the other sections slight by comparison. Instead, Sexton echoes and complicates Josephine’s experience in each of the later two storylines in ways that feel both historically accurate and socially illuminating.

By the time we return to 2014, Josephine is a faded ancestor. But her spirit continues to hover over Ava — and the novel. This intermingling of stories makes an evocative point about the path that black Americans have followed over the past century-and-a-half.