Few moments in musical comedy dazzle more than “A Weekend in the Country,” and Theater Latté Da’s “A Little Night Music” brings off the song with fizzy élan.

We’re in Sweden, around 1900, and there’s to be a house party at the remote home of Madame Armfeldt (Susan Hofflander), a tart dowager who likes to play solitaire and say viciously accurate things about people. As the invitations arrive, those invited to the party — and two who aren’t — discuss what to wear and do. “A Weekend in the Country” is a little play itself, with droll, character-defining lyrics that set up the conflicts to come in the musical’s second act. And, when the song’s over, you can’t believe how much work has been done in terms of moving the show forward. And how much fun it was to take it all in.

Just about every moment of Latté Da’s “Night Music” is just as fun — original director Harold Prince called it “whipped cream with knives.” It’s a light, effervescent show in which all the songs are waltz variations, and Peter Rothstein has directed it as fluidly and romantically as that classic dance. His staging even picks up on the waltz’s circular quality, with a set of actors conversing snappily on half of the stage while, on the other half, actors delicately spirit off furniture from the previous scene.

The design of this “Night Music” is effortless and elegant. Joel Sass’ dreamy set changes very little during the course of the show, but it’s simultaneously a birch forest, a drawing room and the backstage of a theater. Its gauzy curtains sometimes make the agile, onstage band look like ghosts and sometimes make us feel like we’re the ones haunting the action as we spy on 10 characters playing by the rules of their rigid society, so bent on hiding their emotions it’s almost as if they’re acting out their own lives.

Sally Wingert’s Desiree is an actor (and Madame Armfeldt’s daughter), one who is beginning to think of settling down with an old flame (Mark Benninghofen), even if that means putting the pieces together at an awkward party whose guests include two lovers and both of their wives.

It’s a great part for Wingert. She hints that Desiree is finally finding within herself the strength it requires to be vulnerable, finds comedy in places I’ve never noticed (“This is my daughter” does not read like a big laugh line, but get ready for it) and makes “Send in the Clowns” a shimmering, shattering moment. Lighting designer Marcus Dilliard caps off the song with a spotlight that works like a heartbreaking movie close-up. And then Rothstein leaves Wingert on stage for the next several scenes, forcing Desiree to listen to young people’s hopeful talk of love.

There’s not a weak link in the cast, which also benefits from the airy, comic quality Benninghofen lends the sometimes-staid Fredrik, Mabel Weismann’s unfussy wisdom as Desiree’s daughter and Elizabeth Hawkinson’s amusingly biting work as one of Desiree’s romantic rivals.

Hawkinson is on the receiving end of an understated line that brings you up short, making you realize that, between the Champagne-soaked bon mots, “A Little Night Music” is surprisingly observant about the foibles of people in love.

“I’m afraid marriage is not the easiest of relationships,” Benninghofen tells Hawkinson. Um, you think?