When it isn’t being thrown into panicky chiaroscuro for a few moments, The Light in the Piazza is a love story illuminated by a fragile, crepuscular glow. For all the play’s emphasis on light, however, it is the wind that defines this musical’s light-headed sentimentality — the way it steals a woman’s hat, which a young man then captures. Based on Elizabeth Spencer’s 1960 novel, playwright Craig Lucas’ book places the story in Florence, 1953, while composer Adam Guettel’s lush music and lyrics put it somewhere between West Side Story and Sunset Boulevard. From the first harp strings we think this will be a tale of chiffon, ribbons and hankies, where happiness will be menaced only by the merest possibility of trouble.

Margaret Johnson (Christine Andreas) is a Southern matron guiding her 26-year-old daughter, Clara (Elena Shaddow), along a tour of Italy that happens to retrace the itinerary of Margaret’s long-ago honeymoon. While the women ogle Florence’s fountains and statues, a fateful breeze lifts Clara’s hat, which, in a seamless stage effect, flies above the piazza before it is snagged by an awkward young Firenzian named Fabrizio Naccarelli (David Burnham), who wears wire-rimmed glasses and his white shirttails untucked. The boy and girl are mutually smitten, to Margaret’s obvious displeasure. Whenever Clara and Fabrizio get within a few feet of one another, Margaret inserts and stretches herself between them like some human dental dam.

The mother, however, flailing her arms and her Baedeker, doesn’t pose a credible threat to the budding romance, nor do the disapproving transatlantic phone calls from Margaret’s cranky husband, Roy (Brian Sutherland), who is supposedly too tied down with tobacco-business matters to join her in Italy. Besides, Fabrizio’s charming family seems to break down Mom’s objections with each salute!, and Christopher Akerlind’s dreamy lighting design, along with Catherine Zuber’s fanciful period costumes, have Happy Ending written all over them. How can this possibly go wrong?

The answer is Clara herself, who, as a young girl, was the victim of a riding accident that arrested her mental development, which may not make her wedding material as far as the Naccarellis are concerned. We see this in the “Hysteria” scene in which Clara frantically stumbles about a darkened piazza in search of Fabrizio, and later, when she flips out in front of the Naccarellis, hurling insults and wine at Fabrizio’s sister, Franca (Laura Griffith).

Although set in 1953, The Light in the Piazza is very much a part of the literary and cinematic exploration of mental illness in vogue during the late 1950s and early 1960s — an interest in looking at autism and schizophrenia in ways that went beyond Park Avenue psychologizing. Novels and films such as David and Lisa and A Child Is Waiting expressed a poetic humanism that, by accepting damaged children on their own terms, found more hope for their lives than clinical Freudianism could offer. (Spencer’s novel would be released as a film in 1962 with George Hamilton improbably playing Fabrizio.)

For all its tender treatment of mental disability, the musical version of Spencer’s book has unresolved problems that Lucas does not address. The most glaring of these is Clara. She’s described as having the body of a 26-year-old woman and the mind of a 10-year-old. While such proportions may have seemed ideal to American men in the 1950s, today they make us wonder about the life she and Fabrizio are headed toward. Worse, the dim-girl diagnosis isn’t supported by Clara’s dialogue. When she speaks, she sounds like a free-spirited young woman who may not particularly have a lot on her mind — as opposed to a person with a fried cerebral cortex.

Although much of the show’s humor lies in timeworn language misunderstandings (“Your milk, your milk is eh .?.?.” Fabrizio sputters in broken English to a bewildered Clara, who doesn’t sense he’s referring to her skin), Lucas has gambled by having the Italian characters mostly speak in Italian. Sometimes this strategy works — when the Italian is basic enough, or sounds close enough to English so that we can make it out. Other times, we tune it out. At one point Fabrizio’s mother (Diane Sutherland) breaks character and simply explains what’s happening to the audience in English. I could be wrong, but there may be subtler ways of doing this.

The Ahmanson show is the Tony-winning Lincoln Center staging, although of the original cast, only David Burnham, who worked in the New York version as an ensemble member, appears at the Ahmanson. Director Bartlett Sher choreographs the actions around Michael Yeargan’s faux-marble sets expertly enough, and his cast’s voices are competent, but there’s a hole onstage where the drama should be.

With the exception of Burnham’s role as Fabrizio (a full-bodied portrayal of a character who matures from tentative man-child to caring lover), it is the Ahmanson production’s secondary characters who give their best. Andreas overplays Margaret’s mother-hen ticks while betraying little inner turmoil, and Shaddow’s Clara plays her part for an innocence that contains no vulnerability. Happily, Jonathan Hammond turns in a finely tuned performance as Fabrizio’s suave father, who wins over Margaret to the idea of their children marrying — only to find himself falling for Margaret. Laura Griffith also admirably contributes a fiery turn as Fabrizio’s bitter sister.

The Light in the Piazza’s real star, however, is Guettel’s music, which teases our senses. This voluptuous yet mercurial score accomplishes that rarest of feats by flattering listeners with complex melodies while not pandering to audience expectations that have been formed by years of Broadway shows programmed with hollow blues-rock ballads. Guettel gives the show its ache and its gravity — the rest is wind blowing through a set.

THE LIGHT IN THE PIAZZA | Book by CRAIG LUCAS, music and lyrics by ADAM GUETTEL | AHMANSON THEATRE, 135 N. Grand Ave., dwntwn. | Through Dec. 10 | (213) 628-2772

LA Weekly