The lights are bright in Helsinki, at least the selectively focused sunlight and electric glare illuminating the lonely, yearning characters in the films of Aki Kaurismäki. The Finnish writer-director’s 20th film, “Fallen Leaves,” is one of the filmmaker’s drollest and leanest accomplishments — an 80-minute romantic fable beguiling in its simplicity, its unfixed timeframe (the characters listen to Russia’s Ukraine invasion reports on the radio, but the radio typically is a half-century out of date) and its devotion to the essentials.

It unfolds as a story of a woman, a man, a dog and a vaguely hostile socioeconomic urban environment. First, we meet Ansa (Alma Pöysti, a steady marvel and the film’s emotional core), working at a grocery store where she’s dismissed for stealing something already targeted for the trash bin. She moves on to washing dishes at a bar, and then to a factory.

By this time she has met Holappa (Jussi Vatanen, a sort of midway amalgam of Ryan Gosling and James Stewart), a chronic drinker and smoker. Reason? One word: Finland. All the men, Ansa’s confidant (Nuppu Koivu) explains, are swine, though Ansa thinks that description’s unfair to the swine. They don’t really mean it, but they’ve known their share of hard-shell Finns without much in the way of emotional access.

At the karaoke bar one night, Holappa spies Ansa, and vice versa. Their first actual conversation comes later. I’ve never been to Finland, but any current or former Minnesota residents who have lived among the social- emotional Nordic traditions of awkward silence interrupted by the occasional, blurted conversational misjudgment will recognize the behavior in “Fallen Leaves.”

Here’s a sample of the small talk between Holappa and his equally tight-lipped factory pal (Janne Hyytiäinen):

“I’m depressed.”

“Why?”

“Because I drink so much.”

“Why do you drink, then?”

(Pause) “Because I’m depressed.” The exchange is quintessential Kaurismäki patter, delivered by actors smart enough to know “deadpan” can contain multitudes of shading.

Chance encounters and random strokes of terrible or favorable luck inform all the filmmaker’s portraits. A phone number written in a note, almost immediately misplaced; an off-screen near-tragedy involving a passing streetcar; these things happen, no big deal, but they change the course of the central couple’s lives. With his longtime cinematographer Timo Salminen, who has worked with Kaurismäki for 40 years, the director creates a bittersweetly comic panorama of faces, in bars, on the street, in bed, with vivid, not-quite-realistic intensity surrounded by darkness.

Sometimes the darkness takes over, as in Kaurismäki’s earlier, intensely harsh film “The Match Factory Girl.” “Fallen Leaves,” by contrast, strikes an adroit balance between dark and light, stoicism and optimism. There’s a stealth buoyancy at work. Love triumphs after all, and when Ansa winks at her newly reformed fella, her freshly adopted stray dog at her side, it’s like the sun busting out all over Helsinki’s skies.

Pöysti is pitch-perfect throughout as a careworn woman with poetry deep down, as Ibsen said of Hedda Gabler. Everybody in a Kaurismäki film has that same glimmer of poetry underneath the “Finnish Jack Webb School of Underplaying” exterior. That’s true right down to Ansa’s stray dog, who wanders into this melancholic charmer of a story — and decides to stay.

No MPA rating (some language)

Running time: 1:20

How to watch: In theaters