The first Christmas film of the season blows in from the cold with its collar turned up and soot on its hands, offering a few crumbs of comfort that are made to feel like a feast. It’s adapted by Enda Walsh from Claire Keegan’s novella and directed in a series of soft grey lines by Tim Mielants, who conjures an 80s small-town Ireland that’s as hazardous as a haunted house. The tale’s message of hardship and self-sacrifice won’t sit well with those who like their festive movies full of abundant good cheer. Still, Small Things Like These casts a powerful spell.

Fresh from his best actor Oscar win for Oppenheimer, Cillian Murphy produces and stars as melancholic Bill Furlong, who can’t seem to look anyone in the eye. Bill was born out of wedlock, born into shame, but now has a home and a family and a job hauling truckloads of coal around town. His life is fine, or at least an improvement on what went before. Then one winter morning he discovers a young woman in the shed outside the local Magdalene laundry. The past is not dead; it is still whispering in his ear.

Mielants and Walsh pace their Samaritan tale to perfection, which is to say that Small Things Like These plays out as a halting study in human decency, taking the high road in hesitant steps as it pits Murphy’s timid coal merchant against Emily Watson’s unblinking mother superior. Bill’s not an obvious hero; he carries the faint air of defeat. Yet he can’t look away and knows that the cost will be steep. If his small act of kindness veers close to martyrdom, it is all the more noble and precious for that.

• In UK and Irish cinemas