There isn’t a glint of glitter, a ripped body or a pair of jazz hands to be found in “Once,” which slid into town Tuesday night at the Orpheum. Don’t look for high-kicking dance lines either, levitating princesses or pyrotechnics.

The little musical (which, it should be pointed out, won eight Tonys) has the patina of age and the weary atmosphere of world-damaged souls. It is built from a mere slip of a plot, with the conceit that singing actors play not only their roles but their own instruments — guitars, pianos, violins, mandolins, banjos. There’s your orchestra, mate.

If this show is to lift your spirits and reward time spent in the theater, it will be on the decidedly simple terms of heart — and a romance that goes deeper than infatuation.

Do not assume, though, that this is wimpy stuff. Directed by John Tiffany, “Once” shades to a blue-collar aesthetic, replete with the ragged and rough chemistry of an Irish pub.

Playwright Enda Walsh wrote the book based on the 2007 film about a Dublin street musician whose romantic breakup has left him bereft. As the musical opens, actor Stuart Ward’s “Guy” is howling through the song “Leave,” like an emotional exorcism. Dani de Waal’s “Girl” recognizes that heartache has stalled Guy’s creative engine and makes it her project to revive his dreams — and get him back with his old paramour.

“These songs must be sung, for you, for me, for anyone who has lost love,” the Girl tells Guy.

Guy is a songwriter and Girl plays the piano in the music shop of big Billy (Evan Harrington) so they set out to make a demo CD. Here, “Once” shows off its heart and essence: These people are not simply singing and performing music, they are making the music, and that process of creation feels real and wonderful to witness.

In the film, Glen Hansard and Markéta Irglovà played Guy and Girl, and they wrote the songs that have been imported into the musical. Here again, set aside your Broadway expectations. The alternative-rock songs become part of the life of these characters, not moments of escape or introspection.

It took time for the show on Tuesday night to find its footing on Bob Crowley’s aptly appointed pub set design, which becomes other locations through props and tables. The action is more exaggerated, jumpier than the film, which was a quiet, intimate affair. Then Ward and de Waal click on “Falling Slowly” (which won the best song Oscar) and the vocabulary of music and heart begins to express its absolute necessity.

“Once,” kept on a brisk pace by Tiffany, has unexpected small and beautiful moments — when Guy and Girl are looking for a bank loan and songs erupt at the manager’s desk, when performers play their instruments and manage to dance through the first-act closer (choreographed by Steven Hoggett), when the full gang roars through “When Your Mind’s Made Up” in the recording studio.

A friend complained that “Once” felt slight. Yeah, on purpose, I sense. Otherwise, you crush a fragile story about unconsummated but desperately urgent love and the power of music to transform people. If that can’t stir you, then all the glam in all the world will not redeem this show for you.