We may have reached the unofficial end of summer, but there’s still time to squeeze in a few smiles. For you see, according to Madame Armfeldt, the summer night indeed smiles three times: once for the young, once for the fools who know too little, and once for those who know too much. And Boston theatergoers wise enough to find themselves in the audience of the Huntington Theatre Company’s production of Stephen Sondheim’s 1973 masterwork, A Little Night Music, will find themselves smiling right back.

As far as musicals go, they don’t get much more elegant than this lavish and luscious exploration of mortality, morality, love, and—yes—sex. Adapted from Ingmar Bergman’s 1955 film Smiles of a Summer Night, Sondheim’s A Little Night Music unfolds in turn-of-the-century Sweden around Desiree Armfeldt, an unsatisfied well-known actress of a certain age currently on tour and who finds herself in the hometown of an old lover, who is newly married to a young virgin. With a temptation of such inexorable proximity, the lovers reassemble, but not if Desiree’s present lover—also married—has anything to say about it. While the two espoused suitors grapple over Desiree, the men’s wives, bonding over the anguish of having unfaithful husbands, begin to cook up their own scheme. Take all this drama, plus a handful of other lusty, libidinous characters, and place them in the country estate of Madame Armfeldt, Desiree’s mother, for a weekend getaway: Where she stops, nobody knows.

Huntington Theatre Company artistic director Peter DuBois is at the helm of this Night Music. It’s a show that he’s wanted to direct for years, and he believes the show is just as timely as ever: “Sondheim has captured the imaginations of a whole new generation of theatre makers and theatre goers, and I feel that the themes of A Little Night Music—sex, death, second chances, love—are themes that are eternal … I believe Sondheim is the Shakespeare of our time; the incredible range of themes, thoughts, ideas, and emotions in his work is unparalleled,” DuBois told me. “I’m also drawn to the musical’s notion that until we hit the grave there is always opportunity for second chances.” Thrillingly talented British actress Haydn Gwynne—best known for her Tony and Olivier Award-nominated performance in Billy Elliot—stars as Desiree.

A Little Night Music afforded Sondheim the only Top 40 hit of his career with the aching and regretful “Send in the Clowns.” While the song often sounds quite lovely out of context (I’m partial to Barbra’s), to see the song performed within the musical is to have your heart broken—in the best way possible. Even Catherine Zeta-Jones, who won a Tony Award for her respectable but uneven portrayal of Desiree in the otherwise DOA 2009 Broadway revival, left my heart in my throat. Lucky for us, we’ve got Gwynne. “Rehearsing [the song] with Haydn Gwynne is spine-tingling—to see how she carries the emotional weight of the scene into the song … no recording has ever captured the nuance and texture of a stage performance,” said DuBois.

While DuBois’ production will remain true to the period—“Why mess with something that is so elegant and beautiful?” he said—the concept of his Night Music is more than just the silver birch trees and straightforward approach that many have come to expect of the show. “We have created our own theatrical language to tell that story—musically, visually, physically, emotionally—and we’re using Desiree’s livelihood, the theater, as the framework for our staging,” said DuBois.

A Little Night Music is not merely a bedroom farce with a hit song and plush garb. As is always the case with Sondheim, something darker lurks beneath. With a deliciously satisfying book by Hugh Wheeler, Night Music is at once winsome and worrisome, capricious and cautionary. It is through characters of several generations that we see the promise of youth play out amidst the pain of nostalgia: the careless wide-eyed young lovers and those in middle age “unsure of their lines,” the sweltering closing days of summer and the crisp, moonlit nights with something in the wind.

Might Sondheim himself make the trip to Boston? “Keep your eyes peeled,” DuBois told me. “You never know.”

A LITTLE NIGHT MUSIC. RUNS 9.11-10.11 AT THE HUNTINGTON THEATRE COMPANY, 264 HUNTINGTON AVE., BOSTON. WWW.HUNTINGTONTHEATRE.ORG