Aatsinki: The Story of Arctic Cowboys

  Opens on Friday in Manhattan.

Directed by Jessica Oreck

In Finnish, with English subtitles

1 hour 25 minutes; not rated

A vast herd of wild reindeer flows through winter woods, a river of dun and white spooked by the helicopter hovering overhead. From above, we follow their antlers, some soaring high into the air, others stubby and velvet-coated. The scene is so dreamily beautiful that later, when a membranous, blue-gray mass swells from a gash in the heaving abdomen of a slaughtered calf, the image feels like a slap in the face.

“Aatsinki: The Story of Arctic Cowboys” is filled with moments like this. Observing a year in the life of the brothers Aarne and Lasse Aatsinki, reindeer herders in Finnish Lapland, this challenging and mesmerizing documentary captures horror and joy with the same gorgeous dispassion.

Neither explaining the action nor commenting on it, the director, Jessica Oreck, isn’t arguing a case for this dying way of life; her aloof, disciplined aesthetic remains strictly show, not tell. As the seasons slip past, and the killing floor is replaced by a caravan of Christmas tourists enjoying sleigh rides in milky light, we figure things out for ourselves. Or not, as the case may be.

Like chords in a song or phrases in a poem, certain activities — whittling wood, tagging ears, boiling water — repeat with ceremonious solemnity, establishing a vital rhythm that’s emphasized by the film’s naturalistic soundtrack. The Aatsinki brothers don’t say much, but their grunting, snuffling animals, as well as the roar of their snowmobiles, could not speak more eloquently to a people frozen between tradition and modernity.