From “28 Days Later” through to his recent, Oscar-nominated turn in “Oppenheimer,” Cillian Murphy has cultivated a reputation as a strong, silent type — all while resisting the inscrutability associated with that masculine cliché. His beautiful, sharp-boned face twitches and tightens and teems with feeling. Closeups always catch it thinking, wrestling with surges of vulnerability or violence, or watching other characters in turn. It’s always busy, never blank. A story of the unspeakable gradually leaving the realm of the unsaid, “Small Things Like These” rests on both his quiet and his disquiet as an actor. As a blue-collar family man growing increasingly alert to misdeeds in the sacred heart of his community, he’s not just the conscience of Belgian director Tim Mielants‘ delicate, understated film, but its live emotional current.

For if Murphy’s character Bill Furlong is quiet, the town around him is practically petrified. A sleepy settlement in Ireland’s County Wexford, New Ross is, like the rest of the country, dourly in thrall to the Catholic Church, with local convent head Sister Mary (Emily Watson) held by all in tense, unquestioned esteem. The year is 1985, and a great institutional reckoning is some way off. Still, people know enough to look tactfully away from the convent’s imposing, ever-closed doors when young girls in trouble are pushed through them. A single wall separates the building from the school attended by more fortunate children, Bill’s five daughters among them, and if any cries or screams are heard through the bricks, they’re quickly unheard by communal agreement.

Deftly adapted by playwright Enda Walsh from Claire Keegan’s Booker-shortlisted novella, “Small Things Like These” counts on its audience to know what’s happening behind those doors — a litany of abuses visited upon the “fallen” women and children confined in Ireland’s corrupt, Catholic-run Magdalene laundries. Whether through news exposés, artworks like Peter Mullan’s “The Magdalene Sisters,” or the anguished testimony of victims like the late Sinéad O’Connor, the truth has since been unpacked, and neither Keegan’s book nor Mielants’ film is out to graphically rake through it. Instead, the drama here lies in the community blind spots, maintained through equal parts innocence and avoidance, that enabled these institutions to prosper for as long as they did.

“To get on in this life, there are things you have to ignore.” So says Bill’s steely, straight-and-narrow wife Eileen (Eileen Walsh) to her husband when he shows alarming signs of looking into the void — and that’s as close as anyone comes to vocally acknowledging something rotten in a God-fearing community that appears to fear God’s appointed officers most of all. Naturally taciturn anyway, Bill complies, though he’s always stood a little outside the circle. Born to an unwed teenage mother who escaped the laundries, instead finding sanctuary with wealthy, kindly landowner Mrs. Wilson (Michelle Fairley), he bristles at any shaming of women in equivalent circumstances. But his own guilt and grief have given him a heavy gait and a sleepless mind. When he scrubs his hands at the end of a day’s work delivering coal and fuel to his fellow townspeople, it’s with a vigor that seeks a new, unsullied skin altogether.

Set in the days leading up to Christmas, “Small Things Like These” makes a virtue of the midwinter’s stingy daylight — which, in this stretch of southwest Ireland, is dull even at its noontime brightest — and of darkness warmed by seasonal, face-saving lights and garlands. Cinematographer Frank van den Eeden (“Close”) works in hues of canvas and rust, picking out pools of half-lit clarity amid the drear, but the effect is never cozy. Tension over things unseen permeates every frame, and that’s before Bill, while delivering coal to the convent, steps uninvited past the doors, into a veritable fug of oak-panelled oppression.

Sarah (Zara Devlin), a newly admitted young mother, accosts him with a desperate plea to help her escape. She’s as frenzied as Sister Mary is immaculately calm in her interception. Assisted by Watson’s cold, uncreased performance, Mielants toys with the gothic atmospherics of ecclesiastical horror, but doesn’t need to push them very far. There’s menace enough here in everyday reality, down to the few pound notes that Mary pointedly folds into a Christmas card, and hands Bill as a family gift. He doesn’t refuse it, but doesn’t open it either. Any resistance is qualified, and ultimately ineffectual, in this culture of open secrecy, built on petty standards of politeness and neighborly compliance.

Walsh’s spare, sharp dialogue is alive to the conversational traps and swerves that keep small-town consciences closed if not clean, while Mielants contributes an outsider’s view, shooting the tight streets, cramped pubs and adjoining, two-up-two-down houses of New Ross with a reserve that emphasizes its exclusive closeness. But it’s Murphy’s exquisitely pained performance, unclenching by fine degrees into something like grace, that gives “Small Things Like These” its eventual, fist-in-the-gut power, even as the film evades melodramatic confrontation to the last, ending elegantly at a point where many other stories might choose to begin. Action supplants the need for questioning, or negotiation, or talk at all: At least for a moment, Murphy’s face creases and tenses with enough defiant moral certainty to correct a church, a country, and a history of sorrow.