"Martin Guerre," the latest musical from Alain Boublil and Claude-Michel Schonberg ("Les Miserables," "Miss Saigon") which just opened at the Kennedy Center Opera House, has been a work-in-progress since the creators decided in 1996 to rework the original. And despite winning the 1997 Olivier Award for London's Best Musical, it remains a work-in-progress, earnest but theatrically inert.

The show is based on the same French legend as the 1982 movie "The Return of Martin Guerre": In 16th-century France, a man comes to the village of Artigat claiming to be the same Martin Guerre who deserted his wife there seven years ago. The movie was an "Is he or isn't he?" tale, a mystery story with the wife's ambivalent motivations at its center. The musical, which lets us know right from the start that the returning man is not Guerre, hasn't decided what it is.

Watching the show, you never understand why the authors wanted to tell an audience this particular story. With the mystery element gone, it's not even clear what the story is. Is it about a man who seizes the chance for a new life? A woman who for true love would live a lie? A man who learns to forgive? All three? Focus lurches back and forth among the characters, glancing off all sorts of ideas--there are songs about identity, love and individual freedom--without dramatizing or illuminating any of them.

Additional confusion is added by Protestant-Catholic antagonism in the village. The opposing religious believers might as well be rival gang members for all we understand about their conflict. The village also celebrates a quasi-pagan harvest festival complete with king and queen.

Fertility appears to be very much an issue, with, in a flashback, the villagers badgering the newly married Martin (Hugh Panaro) to produce a child, and insisting that his failure to do so is the reason there's too much rain. The villagers are inconsistent on this matter: Later, the deserted wife's childlessness is believed to cause too much sun. And when the impostor Arnaud (Stephen R. Buntrock) arrives, the drought miraculously ends. If this all means something, what that is is never made clear.

The insistence of the village on the Guerres' producing a child becomes inadvertently comic, with people surrounding the house the first night Arnaud is there to make sure he stays and does his duty. Certainly, there are no children in this village. But is this because of a budget consideration based on cast size, or is Artigat meant to be sterile, perhaps cursed?

Why is Martin's virility of such importance when no one else's seems to be? And why is he such a reluctant husband? He claims that, at 14, he was forced to marry too young, but given the nature of 14-year-old boys and the beauty of the woman he weds, Bertrande (Erin Dilly), the explanation is unconvincing. When the first song, "Without You as a Friend," is about Martin and Arnaud's affection for each other, you begin to wonder whether perhaps Martin is simply dealing with what today we call gender issues.

As if things weren't cluttered enough, the authors toss in an idiot youth, Benoit (Michael Arnold), who is in love with a female scarecrow. She's a sturdy lass: He swings on her as if she were a jungle gym. He also sings her a love song. Benoit later comes in handy in resolving a troublesome plot point: He dashes from one side of the stage to the other, pausing only to whack a character to death with the stick that is all that remains of his beloved scarecrow (Don't ask).

The brilliant John Napier ("Nicholas Nickleby," "Les Miserables," "Miss Saigon") has inexplicably designed a set of vertical, weathered boards that makes "Martin Guerre" look as if it's taking place in a barn. Admittedly, this suits David Bolger's stomping, clomping dances, which unfortunately emphasize Schonberg's tendency to write songs in pounding march- and waltz-time.

Schonberg's music is, as always, heroically melodic, and the cast members have the clear, powerful voices necessary to put the songs across. But like the book, the score lacks dramatic focus and narrative line; it ends up sounding pretty but flabby, like something a Schonberg imitator might write.

No one involved seems to have realized that what they've come up with is slightly ridiculous. Everything is presented so soberly and well-meaningly that you can't laugh at the excesses the way you can with more pompous shows. A bravura director might have disguised some of the problems with show-biz flash, as Nicholas Hytner did in "Miss Saigon" when he dragged on a 12-foot statue of Ho Chi Minh or landed a helicopter onstage. Vulgarity at least has some energy. But director Conall Morrison is new to musicals, and in his tactful hands, "Martin Guerre" just humbly plods its way to a new musical theater combination: ludicrous but tasteful.

Martin Guerre, book by Alain Boublil and Claude-Michel Schonberg, music by Claude-Michel Schonberg, lyrics by Alain Boublil and Stephen Clark. Directed by Conall Morrison. Costumes, Andreane Neofitou; lights, Howard Harrison; sound, Andrew Bruce and Mark Menard; orchestrations, William David Brohn; musical supervision, David Caddick; musical direction, Kevin Stites. With Jose llana, John Leslie Wolfe, Kathy Taylor, John Herrera, Michael Arnold, Alvin Crawford, Angela Lockett, D.C. Anderson, Amy Bodnar, Pierce Peter Brandt, Susan Dawn Carson, Adam Dyer, Hunter Foster, Chris Lamontagne, Jodie Langel, Megan Osterhaus, Sean Jeremy Palmer, Joe Paparella, Sophia Salguero, Bill Szobody. At the Kennedy Center through Jan. 16. Call 202-467-4600.

CAPTION: Hugh Panaro, left, and Stephen Buntrock as Martin Guerre and the impostor Arnaud.

CAPTION: Stephen Buntrock and Erin Dilly as Arnaud and Bertrande in "Martin Guerre."