Genealogy meets mythology in “Moving Midway,” a documentary that examines the ugly legacy of slavery and the difficulties of reconciliation through the lens of a Southern antebellum mansion that is literally being uprooted — unmoored, placed on a truck, and transported off the plantation on which it stood for generations.

The film critic Godfrey Cheshire, a native of North Carolina, undertook the making of the film when he learned, in 2004, that his cousins had decided to move it off the land it had occupied for centuries in order to escape the encroaching noise of suburbia. Mr. Cheshire has fond memories of this place, having spent time there as a boy. But today he is a New Yorker with an entrenched sense of both Southern heritage and Northern intellectualism. He undertook this visual journey, in no small part, to reconcile two halves of himself that seemed bitterly at odds: the boy who retains fond memories of this plantation oasis, and the man all too aware of its poisoned history.

In dealing with these two disparate themes, “Moving Midway,” which opens Friday at IFC Center, must first address the wider plantation myth in American popular culture. Long seen as a sanctuary of solitude, sophistication, and high society — crystallized, in the cinema Mr. Cheshire cherishes, in “Gone With the Wind” — the plantation may have been a place of refinement, but it was also a place of agony and a representation of the two-tiered economic model so essential to the pre-Civil War South. Slaves toiled and bled on the grounds of Midway. Yet when Mr. Cheshire heard that his cousin planned to move the house, he was reminded of the tranquility and communal joy he once found on its front porch. So what is this place, Mr. Cheshire seems to be asking in the film he decided to make: heaven or hell?

A little digging goes a long way. As Mr. Cheshire traces his family line, he learns the history of the land — how it was bequeathed to his ancestors and how it has been passed down through the generations. The most stunning revelation involves the man who originally built the house, and the affair he had with a black cook long before the Civil War. The discovery, made during production, has profound ramifications for Mr. Cheshire. It turns out that the illicit relationship yielded children, and that Mr. Cheshire is related to a line of mixed-race descendants.

Suddenly, his exhumation of Southern ghosts has found its way into the filmmaker’s own closet. Naturally, he sets out to find these relatives, who trace their lineage both to slaves and slave masters. Between trips to North Carolina, Mr. Cheshire is flabbergasted when he stumbles upon a letter to the editor of the New York Times that bears the same family name he’s been researching. When he phones the writer, Robert Hinton, both are astonished to learn of their relation. In their subsequent meetings and conversations, an inspiring friendship between the two worlds takes root.

But Mr. Hinton, a professor in NYU’s Africana Studies Program, emerges here as something more than just another character in the film. As he accompanies Mr. Cheshire south, he acts as a sounding board for the director, offering a different perspective to this personal journey and bringing his own emotional baggage to the table. Tellingly, Mr. Hinton admits late in the film that he always dreamt of meeting someone from Mr. Cheshire’s family, and always hoped that he would hate whoever it was. When the house is hoisted off its foundations, the men break champagne bottles on the steel girders supporting it, celebrating the beginning of a much different era for the structure.

Having receded into an insular story of one unusual American family, “Moving Midway” leaves itself vulnerable to scrutiny. Where is the larger critical discussion of the antebellum South and its legacy? What about other nations and cultures that have revolted against the plantation system? (Haiti comes to mind.) Mr. Cheshire ultimately leaves behind a major opportunity to forge a much wider conversation.

But perhaps that was unavoidable. The further Messrs. Cheshire and Hinton trace the true meaning of the house, the more “Moving Midway” ceases to be a purely intellectual exercise. Mr. Cheshire has real guilt, and Mr. Hinton has real rage, and their personalities propel the second half of this story. By scrutinizing the things that divide these men, we find the divisions that have informed modern American life — North and South, past and present, black and white. Late in the film, descendents of the plantation’s slaves drive to Midway, which has been planted in its new plot of earth. Seemingly returning to the scene of the crime, they are instead forging a new chapter. It’s a powerful and palpable act of reconciliation, and Mr. Cheshire doesn’t make the mistake of overplaying his hand. He films the moment, allowing the images to speak for themselves. It is a perfect, critic-proof ending for this critic’s heartfelt documentary.

ssnyder@nysun.com