There are a limited number of tropes common to “the prison picture.”

“Normal” guy gets tossed in the joint, where he adapts to the savagery or dies (see the popular “Shot Caller”). Dodging rape or death in the shower, coping with the Big House hierarchy, tattoos, “shivs,” corrupt, sadistic guards — rare is the prison picture where these elements aren’t the building blocks of the story.

This ordinary person bent by a twisted system drives “Orange is the New Black” and most other variations of the “in stir” genre.

Set your story overseas, and everything — the stakes, the violence, the corruption and the life disruption are just dialed up. Hell, even Bridget Jones had her moment of truth in a Thai prison.

“A Prayer Before Dawn” hurls a violent man into this world of violence, sort of a “Bronson” parked in “The Bangkok Hilton,” as it is called. But this true story of Brit boxer Billy Moore’s ordeal dodges a few genre conventions and turns toward “Midnight Express” in its relentless violence, fish-out-of-water sense of displacement and rare moments of humanity.

It’s not a reinvention of the genre, but it is a fairly engrossing variation on a theme. And that’s in large part due to the violence — sexual and otherwise — it recreates.

Joe Cole of TV’s “Peaky Blinders” plays Moore, a Brit kicking around Bangkok’s underground fighting scene, only not kicking enough to win. He’s an over-matched boxer in a Muay Thai MMA world, tough as nails, always on the wrong side of the law and addicted to yaba, that methamphetamine and caffeine blend that is Thailand’s contribution to illegal drug culture.

Billy gets nicked, and we skip straight past the trial and to his introduction to Thai prison life. The sea of disreputable humanity that surrounds him, the sheer scale of everything from that indoctrination strip/search to the 70 inmates (one dead) packed into his cell, tells us that tough guy or not, being slightly bigger and paler is not going to help our lad fit in with this bunch.

That first trip to the bathroom is terrifying and traumatic. Resisting the “cell boss” (Panya Yimmumphai), covered in tattoos, metal-toothed and surrounded by tough lackeys, is futile. None of that “fight the toughest guy in the yard” cliched BS. Resisting the corrupt guards won’t do him any good, either.

“No family, no money, no cigarettes” is the one English phrase they know.

Cole and the script don’t give this guy much of an interior life, but Billy seems to accept his fate, hunting for angles that allow him to get by – mastering the cigarette economy that prisons the world over traffic in, for instance.

The gambling here is over Siamese Fighting Fish fights (a funny touch). Conjugal visits? Those are from prostitutes, Thailand’s infamous “Ladyboys,” one of whom, named Fame (Pornchanok Mabklang) speaks English and starts to help him out, that one human lifeline to “outside” that Billy can count on.

The screenplay emphasizes Billy’s total immersion in this experience — hurled into anarchic chaos, speaking little of the language (the real Billy Moore taught English to the locals, supplementing  that salary with his back-alley boxing), trying to understand each fresh threat, trying to make himself understood.

Subtitles are rarely provided. We hear what Billy hears, see what Billy sees, and try to figure out what’s happening or about to happen the same way he does.

His salvation, after many trips to “the hole” and narrow escapes from death, is fighting. There’s a gym, guys train under the tutelage of a tall, charismatic, chain-smoking Muay Thai master played by Somlock Kamsing, the most impressive of several real fighters cast in supporting roles. 

It’s ancient history to generations of moviegoers now, but Alan Parker’s “Midnight Express,” scripted by Oliver Stone and about an American “Billy” imprisoned in Turkey, is the closest analog to “A Prayer Before Dawn.” That’s the gold standard for “locked-up abroad” films, but far more of a thriller (and more harrowing and emotional) than “Prayer.”

Little that we see here hasn’t turned up in other prison films, and there’s not enough to Cole’s performance to make Billy a wholly sympathetic, iconic hero/survivor. We root for him because that’s pre-ordained, fear for him because he’s our proxy in this Third World Hell.

“A Prayer Before Dawn” still manages to tell a gritty story without blinking or ever looking away, a sobering look at how even the fittest among “us” would be lucky to survive the murderous world Billy Moore misbehaved his way into.

MPAA Rating: R for strong violence including a brutal rape sequence, drug use and language throughout, some sexual content and nudity

Cast: Joe Cole, Pornchanok Mabklang, Panya Yimmumphai

Credits:Directed by Jean-Stéphane Sauvaire, script by Jonathan Hirschbein, Nick Saltrese. An A24 release.

Running time: 1:53