Grade: B+

It’s a musical that doesn’t follow convention—the characters don’t burst into extraneous songs “integrated” into the action, but sing precisely because they’re performers themselves—and a romance that doesn’t end the way you might expect. But though (or perhaps because) it’s so atypical, “Once” is a real charmer. In its low-key, gentle way this small-scaled Irish picture wins you over without appearing even to try.

There’s not much story here. An unnamed guy (Glen Hansard, lead singer/songwriter of the Irish rock group The Frames) is a Dublin busker, a street musician performing his own compositions while working with his Dad (Bill Hodnett) in a vacuum cleaner repair shop. Still nursing the loss of his girlfriend, who’s moved to London, he’s approached one day by the girl (Marketa Irglova, who’s recorded an album with Hansard), a Czech immigrant who supports her mother and young son (the husband is still back home) by selling flowers on the street, and who’s impressed by his music and just happens to have a broken vacuum. She’s a musician, too—a pianist—and by the next day they’re performing one of his songs together at a music shop whose clerk lets her use an instrument over the lunch hour. And shortly thereafter they’re applying for a bank loan to rent a recording studio so that he can make a disc of his songs.

“Once” is undeniably a mere wisp of a tale, but it avoids the curse of cuteness despite the fact that each and every one of the characters is nice (even the unexpected ones) and it seems to be headed for a foregone conclusion (though it might just surprise you). That’s due not merely to the naturalness of Hansard and Irglova, but to the unforced approach of writer-director John Carney and Hansard’s songs, which meet the emotional needs of the story without ever seeming in the least intrusive, as the tunes in even the best of musicals so often do. The appearance of the movie is just right, too, with Tim Fleming’s unpretentious but fluent camerawork perfectly complementing the deceptive plainness of Carney’s storytelling.

It may be titled “Once,” but this movie is so emotionally resonant and exuberantly enjoyable that you might just want to see it more than that.