In “Boy Erased,” Jared Eamons, an Arkansas teenager, comes down to the kitchen one night and confesses to his parents that he’s sexually attracted to men. The room goes quiet, but you can hear the alarms shrieking, and within minutes church elders are summoned to the home. The Eamons family is literally in a gay panic.

“In your heart,” says Jared’s father, Marshall, an otherwise jovial Baptist preacher played by Russell Crowe, “do you want to change?” Jared does, of course. What son doesn’t want to please his father?

Based on Garrard Conley’s 2016 memoir, “Boy Erased” follows Jared, a sensitive and good-hearted kid played with deep sensitivity by Lucas Hedges, as he enters a Christian, ex-gay conversion program called Love in Action. The film portrays it as a through-the-looking-glass place where science, modern social norms and plain horse sense take a back seat to the Bible-based belief that homosexuality is a sin. Lead counselor Victor Sykes, a tough-love type played by the film’s writer and director, Joel Edgerton, says being gay is no different than being an alcoholic or a domestic abuser.

“It’s a choice,” he says. “It’s behavioral.”

Though this movie has changed many names (save for that of the conversion program), it has the undeniable ring of truth. It’s filled with memorable details: a high-strung military veteran (a very good Flea, of the Red Hot Chili Peppers) who teaches the men how to firmly shake a hand; a “moral inventory” of one’s family, meant to spot other genetic weaklings; a bizarre and abusive “funeral” meant to scare one recidivist young member straight. Outside, staying in a nearby hotel room, Jared’s mother, Nancy (Nicole Kidman, beautifully balanced between subservient wife and protective mother), begins to wonder about the program’s professional bona fides: Their manuals misspell “God” as “Dog.”

“Boy Erased” is a subtle, understated film that feels less like an institutional exposé than an attempt to speak to those of a certain mindset. The movie never demonizes Jared’s parents, or the Love In Action staff, even when it becomes clear that a program built on self-loathing can actually cost lives. In that sense, “Boy Erased” is the most heart-wrenching kind of story, one in which everyone is trying to do the right thing.