The year is 1993. The place is God's Promise, a Christian rehabilitation camp in the middle of a wooded Montana nowhere. The central character, played by Chloë Grace Moretz, is a 12th grader whose guardian sent her off for conversion therapy after she got caught making out with a female classmate in the back seat of a car on prom night. The picture is the winner of the 2018 Grand Jury Prize, the Sundance Film Festival's highest honor.

The Miseducation of Cameron Post could have gone in any number of directions. It's easy to imagine, for example, a Get Out-style cocktail of social comment and horror in its portrait of teenagers forced to undergo ex-gay brainwashing. The subject of fundamentalist quacks claiming to have a cure for homosexuality is ripe for blackly comic satire. Another creative team might have gone with a YA One Flew Over the Cuckoo's Nest.

Instead, what director Desiree Akhavan (Appropriate Behavior) and cowriter Cecilia Frugiuele saw as the most effective, emotionally resonant and enlightening treatment of Emily M. Danforth's acclaimed 2012 novel was a deceptively simple, straightforward character study. Moretz delivers a quietly nuanced turn as a young woman dropped behind enemy lines and taken prisoner but determined not to crack.

From the moment we climb the long driveway to the secluded facility and find Reverend Rick (John Gallagher Jr.) strumming his acoustic guitar and singing a saccharine Jesus ditty to a captive audience of kids, we know we're not in Kansas anymore. The people who run the place — particularly its director, Dr. Lydia March (Zero Dark Thirty's Jennifer Ehle) — come off as leaders of a cult. They're clearly deluded. The only question is: Are they dangerous?

Cameron is a person whom life has taught harsh truths at a tender age. Both her parents died in an automobile crash. As a result, she is wise beyond her years, and wary. She's also smart enough to keep her mouth shut and her eyes open.

The film follows Cameron as she learns to navigate this weird new world: telling her Kool-Aid-chugging roommate just enough to register as friendly; getting the hang of what the counselors want to hear in group therapy; and watching the other kids, alert for signs of intelligent life. Eventually, she finds kindred spirits in Adam (Forrest Goodluck), whom she dubs "Native American David Bowie"; and Jane (Sasha Lane), a free spirit with a fake leg that comes in handy for hiding her stash.

The movie's funniest, most vibrant scenes are those the three share, such as an impromptu kitchen sing-along to 4 Non Blondes' "What's Up." Naturally, Nurse Ratched — I mean Dr. March — walks in and sees to it that the music is over sooner than it should be.

She's responsible for far worse. Passive-aggressively undermining her charges' sense of self with a pseudoscientific overdose of God and guilt, March drives at least one minor to the brink of major catastrophe. "What feels like fun is actually the enemy," she says early on with a smile.

The party line of the place is so creepy and suspect that the present-day viewer is likely to wonder whether such monstrous nonsense could really have happened. Of course, it still does. Though discredited, conversion therapy is somehow legal in 41 states (not in Vermont). America hardly needs another reason to feel ashamed right now. All the more reason to take a lesson from The Miseducation of Cameron Post.