Robert Eggers's The Witch is about a true-life American nightmare: being a Puritan teenager in 1630. Thomasin (Anya Taylor-Joy), a big-eyed girl who looks like a mouse wearing a bonnet, has been bred to be obedient and dull. Her church has banned makeup, jewelry, dancing, reading, music, theater, and Christmas. Worse, her parents — both British city folk – just freaked out and moved their entire family to colonial New England, a place so primitive the windows don't have glass.

Ugh, whatever. There's only 5,000 people in this country — Thomasin could learn to fit in. Then, in the opening scene, her dad (Ralph Ineson) acts like such a jerk that their family is banished. Mom, Dad, Thomasin, and her four younger siblings are forced to live alone at the edge of total wilderness, a maze of skinny trees that gobble up the sun. Starvation looms. And if Thomasin complains that her ultra-religious parents are stubborn fools who don't even know how to farm, they could lash out and claim she's possessed by the devil — and they might even believe it.

With a setup this dire, this solemn horror flick doesn't even need a witch. But Eggers gives us one anyway, a hunched crone (the perfectly named Bathsheba Garnett) who shows up in the first 10 minutes to steal Thomasin's baby brother and mash him into jelly. We hear the wet smacking of infant legs pounded into goo. The sound is as impossible to ignore as the witch's red cape, the only pop of color in this miserable, gray world. Eggers has made his point: This isn't scaredy-pants paranoid Salem — this witch is real. The movie savors the witch's carnal wickedness: her gore-smeared body, her criminally long hair, her big-boobed, eerily modern model beauty, which has the plumped, almost plastic look of a Robin Thicke backup dancer. (I guess blood spells worked like ye olde Botox?)

When the film cuts back to stressed-out Thomasin, hustling to do her life-or-death chores while babysitting an obnoxious pair of twins, being a witch doesn't seem so bad. Four hundred years ago, a young girl with a mind of her own was half-damned already. Though Thomasin tries to be good, society is so unforgiving that she could go to hell for playing on the Sabbath. Just being a girl is dangerous enough, at least to demon hunters like the real-life Heinrich Kramer, who warned that “all witchcraft comes from carnal lust, which is in women insatiable.”

Eggers disagrees. (Pity, the movie would be more fun if Thomasin readily embraced her inner party goth.) The only carnal lust here comes from Thomasin's younger brother Caleb (Harvey Scrimshaw), a sad and serious boy who keeps peeping down his sister's three layers of underwear. Yet, even if Thomasin noticed — which the innocent dear doesn't — her parents would blame her for it anyway. This is, as Eggers makes clear, a time before science lit up the darkness. (The cinematography is so dour that candles radiate as much light as bananas.) Houses and heads are filled with shadows. When nothing has an explanation, no one can be trusted. Everything is an omen, from the rabbit that gives dad a dirty look to the bloody chicken eggs and bloody goat's milk that remind us that this world still links fertility to the supernatural. As soon as mom (Kate Dickie) comments that Thomasin “hath begot the sign of her womanhood,” she threatens to kick her daughter out of the house.

Eggers is so faithful to the period dialogue that big scenes are in danger of summoning giggles, like when Thomasin's dad yelps, “'Did ye make some unholy bond with that goat!” Like the Puritans themselves, the movie shuns drama. It has too much moral virtue for jump scares. The most it gives in to modern movie gimmicks is when the horse vanishes and leaves them stranded, the pioneer equivalent of a dead cell phone. There's not even enough witch. She shows up so infrequently we forget she's there, and so we forget to be afraid — nothing ever leaps out to scream “Boo!”

The Witch's re-creation of colonial life is the scariest part of the movie. This sternness could work if there was no witch at all. Scrap her, and the movie becomes about paranoia: How can Thomasin prove her innocence to a family so ruled by spiritual faith that they sailed across the Atlantic? Eggers broaches the idea, but the script stays stiffly outside the psychological woods. We want Thomasin — anyone — to lash out at the culture that forced her family to the literal brink of existence: a dying farm at the frontier of untamed America. The Witch could be our country's founding ghost story — a fable about a society continually distracted by the wrong enemy. There are real ghouls in the woods. Why do we always wind up attacking each other?