Obsessive characters are abundant in the Stephen Sondheim gallery. Mama Rose, Sweeney Todd, Georges Seurat, the assassins of "Assassins" -- these are relentless, sometimes destructive figures whose manias wreak social or emotional havoc.

Another word for the emotion that drives such characters is, of course, passion. It's all in how you look at it, and in "Passion" -- the admirably performed, fluidly staged fifth production in the Kennedy Center's Sondheim Celebration -- Sondheim and librettist James Lapine try hard to get the audience to see the positive qualities in a frail, gothically obsessive woman named Fosca.

Dramatically, this has nearly always been a tough sell. Yet some of Sondheim's music in "Passion," which is very much like a little opera, is heart-stoppingly rapturous. So it's entirely possible to resist the show's unlikely story (based on the 1981 Italian movie "Passione d'Amore," which came from a 19th-century Italian novel) while being shattered by some of the score's trembling romantic statements. And that's likely how you'll come out of director Eric Schaeffer's confident, smartly performed production.

"Passion," set in 1863 Italy, is a Beauty and the Beast tale. A good-looking soldier named Giorgio gradually gives in to the aggressive, pitiful pleadings of the wretched Fosca. This flies in the face of the usual laws of attraction, which are established in the opening duet between Giorgio (Michael Cerveris, his muscled torso exposed) and his beautiful lover, Clara (Rebecca Luker, blond and strapping in a long sheer nightgown). Together they sing "Happiness," a blissful ode in which they gush about their romance. It's a terribly pretty song, but it leaves room for Fosca to show Giorgio something deeper -- and for Sondheim to find more resonant, burnished musical expression for the profound passions to come.

As the ailing Fosca, the diminutive Judy Kuhn is dressed as a Victorian ghoul. Her black dress comes up to her throat, and her chalky face and raccoon eyes can seem a little disembodied. Still, Kuhn is as intriguing a Fosca as you're likely to find. Sondheim piques your interest in this bizarre figure with a deeply absorbing song, "I Read," and Kuhn skillfully negotiates the difficult number's prickly melody and grand gloom with a strong, slightly quavering voice. In trying to downplay the horror-show aspects of Fosca, Kuhn acts with more mournful sadness than clawing desperation, and her downcast eyes and firm sense of the character's crisp intelligence take her pretty far.

But Fosca's intensity can't help but be overwhelming as she plagues Giorgio with the tenacity of a virus. When she lurks behind Giorgio late in the show, you think, fleetingly, that this is the kind of tale where someone ends up with a knife in the back.

That is why audiences have tittered uncomfortably at portions of "Passion" ever since it first appeared in New York eight years ago. (There has not been a new Sondheim musical since then, by the way.) Actually, snickers weren't heard when Schaeffer directed the show at the 136-seat Signature Theatre a few seasons back, which suggests that in a small room it's possible to cast an impenetrable spell with Sondheim's seamless, quietly surging score.

Schaeffer isn't able to do away entirely with unwanted bits of laughter this time around, but it's hard to imagine how his production at the Eisenhower Theater could be any better. His leading actors are first-rate; Luker is lovely and sensible as Clara, while Cerveris, his head shaved and his expression pointed, brings a spiky handsomeness and quizzical air to Giorgio. They sound fine together, with Luker's clear, warm soprano blending nicely with Cerveris's steely singing.

The supporting roles are largely filled by the festival's chorus of local actors, many from Signature, who have been solid throughout this summer's repertory. And Philip Goodwin, a regular at the Shakespeare Theatre, makes easy work of the meddling military doctor who helps thrust Giorgio and Fosca together.

The show is smartly designed, too, from the desiccated set of sliding louvered panels by Derek McLane to Anne Kennedy's crisp period costumes. Lighting designer Howell Binkley adds some stormy effects near the end, and helps fashion a gorgeous closing silhouette that seems borrowed from "Gone With the Wind."

There is a glaring misstep late in the show, an ill-conceived song that was added for the 1996 London production. It doesn't have a title of its own -- you won't find a song list in your program -- but you can't miss it. It comes when Giorgio steps forward and bellows, "I love Fosca," and, "I was wrong," in a bludgeoning moment that seems more in keeping with the ponderous mock-operas that have lumbered across Broadway for the last two decades.

But most of the rest of the score has magic in it. Sondheim subtly weaves the lyricism of "Happiness" with Fosca's duskier motifs, and the emotional turbulence can be wonderfully disquieting. This is in sharp contrast with Sondheim's tactics in "Merrily We Roll Along," also playing at the Kennedy Center. The crisp songs of "Merrily" come strutting at you with Broadway confidence: bright melodies, big choruses, sad ballads, the works. In "Passion," the songs are part of a nearly unbroken fabric of more meditative sound that's utterly different, yet perfectly suited to the story at hand.

The waltzes of "A Little Night Music," which will offer another sound altogether, are yet to come, and it's staggering to think of the different hues that would have been on display if "Follies" and "Assassins" had been included in this festival. By placing six disparate shows cheek by jowl, the Sondheim Celebration is making a good case that despite his acclaim as a lyricist and brave storyteller, Sondheim's most lasting legacy will be for the unrivaled variety and penetrating depth of his music.

Passion, music and lyrics by Stephen Sondheim, book by James Lapine. Directed by Eric Schaeffer. Through Aug. 23 at the Kennedy Center Eisenhower Theater. Call 202-467-4600.

Trembling romance: Michael Cerveris and Rebecca Luker, as the soldier Giorgio and his lover, Clara, express their happiness in "Passion."Michael Cerveris and Rebecca Luker in "Passion," at the Eisenhower Theater.