“When I think of the farm, I think of mud. … I dreamed in brown.” – Carey Mulligan’s Mississippi farm wife in “Mudbound.”

Just about everyone in director/co-writer Dee Rees’ searing and brutally effective 1940s period piece “Mudbound” is living in some version of Hell on Earth.

Jason Clarke’s Henry McAllan, who has unceremoniously moved his wife and two young daughters from a relatively comfortable small-town life and a tidy little home to a borderline-barren stretch of farmland, is a strong and sturdy and mostly well-meaning man — but he’s a stubborn cuss and he can be mean, and he isn’t interested in bending the least bit to the changing times. He seems incapable of lightness or joy, and is oblivious to his wife’s misery.

Henry’s wife Laura (Carey Mulligan, in a devastatingly effective performance), an “old maid” of 31 when she married Henry, finds herself living in a ramshackle home on that farm, caring for her two daughters, working back-breaking days just to keep the household running, and longing for Saturdays, the one day when she can actually take a bath and wash off all the mud and grime and sweat and tears.

Then there’s Henry’s younger brother Jamie (Garrett Hedlund), who was a dashing, life-of-the-the-party ladies’ man before World War II — but comes home as an alcoholic, broken man, unable to put the war behind him.

The most miserable (in every sense of the word) member of the McAllan family is Henry’s father (Jonathan Banks), a dead-eyed racist with a black heart. You’ll find more charm in your average snake.

Yet for all their troubles and struggles and demons, the McAllans have it far better than the Jacksons, their sharecropper tenants. Crammed into a tiny shack, earning barely enough to keep food on the table, working from sunrise to sunset on the McAllan’s farm, the Jacksons dream of owning and farming their own patch of land — but in the here and now, they’re at the beck and call of the McAllans, night and day, day and night.

Rob Morgan and Mary J. Blige deliver beautifully nuanced performances as Hap and Florence Jackson, the deeply spiritual and astonishingly resilient and fiercely protective parents. The versatile actor Jason Mitchell (“Straight Outta Compton,” “Detroit”) is perhaps the film’s most compelling character: Ronsel, the oldest son of Hap and Florence, who serves with great distinction as a tank commander in World War II and is treated as a liberating hero overseas — only to return to a hometown where he’s considered a rabble-rouser simply because he tries to exit the general store through the front door and not the back way.

Set in that post-World War II Mississippi, which doesn’t seem all that different from post-Civil War Mississippi, and adapted from Hillary Jordan’s novel of the same name, “Mudbound” unwinds the stories of those two families, and how their lives are inextricably, tragically linked.

Bound by their wartime experiences — and by the Post Traumatic Stress Disorder they’re both experiencing, in a time when there wasn’t a name for that condition and nobody wanted to hear about it — Jamie and Ronsel strike up a friendship that revolves around drinking and smoking cigarettes and opening up to one another. They take pains to conceal their friendship — after all, they’re living in a town where many of the so-called pillars of the community have white robes and hoods in their closets — but we feel an inevitable sense of dread about where things are heading.

Meanwhile, Laura finds it hard to deny her chemistry with Jamie, who looks at her and talks to her in a way his big brother (her husband) has never done. Is it so wrong for her to have a moment or two of feeling wanted, of feeling respected, of feeling desired?

In this world, it seems as if every moment of happiness, every glimpse of a better future, is fraught with dangerous consequences.

If it sounds as if “Mudbound” is bleak — yes. It is. As various characters tell the story from their point of view in voice-over, there are times when it seems as if there’s almost no hope for anyone, from the most corrupt and evil SOB’s to the damaged war heroes to the most sympathetic characters: Laura and Florence, the women who spend nearly every waking and dreaming moment worrying about and taking care of others.

But redemption and hope eventually shine through here and there, and when that happens, it’s a beautiful thing.

★★★1⁄2

Netflix presents a film directed by Dee Rees and written by Rees and Virgil Williams. Rated R (for some disturbing violence, brief language and nudity). Running time: 120 minutes. Opens Friday at iPic South Barrington and on Netflix.