Second-worst, fifth-worst, eighth-worst? When a musical is this awful, you pore over your personal Book of the Lame: Was "Taboo" this bad? Surely the jaw dropped further during Robert Cuccioli's famous hair-flinging aria in "Jekyll and Hyde." Then again, there was that once-in-a-lifetime musical salute to garlic in "Dance of the Vampires." But wait: What about the galling dullness of "Urban Cowboy," the chafing dryness of "Dracula," the decrepitude of "Dream"?

So many painful memories to relive and prioritize! The theater's ability to induce something akin to post-traumatic stress disorder is fully realized with a show like "Brooklyn, the Musical," which opened last night at the Plymouth Theatre. Not to be confused with the gritty borough it's named for, "Brooklyn, the Musical" is a plastic bit of amateurishness. The feelings it expresses are about as authentic as a holiday dreamed up by a greeting card company.

The show is presented without a break, a shrewd move on the producers' part. It's far more difficult to leave at intermission if there isn't one.

"Brooklyn, the Musical" is introduced to us by the characters as an urban "fairy tale," a tactic that prepares an audience for the possibility that what it is about to see will not make any sense at all. On this score, "Brooklyn, the Musical" outdoes itself. The show's five characters -- each identified in the program as a type of "City Weed" (I'm as intrigued as you are) -- share the arduous chore of singing their way through the late-'60s rags-to-riches story of a young, female street singer by the name of, yup, Brooklyn (Eden Espinosa).

She grows up to vie in some kind of "American Idol"-inspired showdown at Madison Square Garden with the world's most fabulously gifted and talented R&B star, who calls herself Paradice. As played by Ramona Keller, she is this production's one and only bit of good news. The story behind Paradice's name, by the way, is as dumb as the name itself. But her mano a mano battle with Brooklyn -- who has promised to donate the winning purse to "feed and shelter America's homeless" -- is depicted as the most exciting event to rock the solar system since Neil Armstrong went lunar.

"Brooklyn, the Musical" borrows frantically from shows past. "Godspell," "Rent," "Cats," "The Me Nobody Knows": All are conjured in one way or another. Still, the recycled platitudes here exceed any previously recorded level of cliche. "Float across the rainbow sky to once upon a time," goes one particularly shattering lyric, attributed to the show's book and songwriters, Mark Schoenfeld and Barri McPherson. The dialogue is such that at times you feel as if you're sitting behind home plate, under constant threat of being pummeled by foul balls. "Sometimes with our tears," begins a deep thought uttered by a character named Faith, "we can water roses."

Schoenfeld, apparently, was himself a down-on-his-luck busker at one time, and "Brooklyn, the Musical" seems intended as a homage to the sad stories of the streets. He and McPherson so drown it in artificial sweetener, however, that it relinquishes any claim to vital truth. And the score, a forgettable, generic rock songbook, is an excuse for one loud, driving ballad after another; the real contest here is which of the actors can scat and overemote at the highest volume.

For some reason -- maybe he just wanted to show he could sing -- the fine dramatic actor Kevin Anderson (Biff in the Brian Dennehy revival of "Death of a Salesman") got roped into this venture. He's saddled with a ludicrous role, playing Brooklyn's wayward father, a sensitive, drug-addicted, guitar-playing Vietnam vet who is tempted with heroin on the very night he is supposed to celebrate his public reunion with his daughter onstage at the Garden. His is not the only wasted talent: Cleavant Derricks, one of the original stars of "Dreamgirls," is in the cast, too, playing the Magic Man, the narrator and a mystical being in an Andrew Lloyd Webber-style dreamcoat.

The set, by Ray Klausen, is a rubble-strewn lot. At least the costumes, by Tobin Ost, display some wit: Paradice's gown of police tape, trash bags and bubble wrap is fun, an example of dreck couture. Jeff Calhoun is the director. Safe to say his work here is not exactly a breakthrough.

That the borough of Walt Whitman, Woody Allen and Spike Lee has to share anything with this misbegotten evening is a rank injustice. To paraphrase an aggrieved former secretary of labor, where does Brooklyn go to get its good name back?

Brooklyn, the Musical, book, music and lyrics by Mark Schoenfeld and Barri McPherson. Directed by Jeff Calhoun. Set, Ray Klausen; costumes, Tobin Ost; lighting, Michael Gilliam; sound, Jonathan Deans and Peter Hylenski; music supervision and orchestrations, John McDaniel. With Karen Olivo. Approximately 1 hour 50 minutes. At the Plymouth Theatre, 236 W. 45th St. Call 212-239-6200.

The cast of "Brooklyn, the Musical," belts out a number. Clockwise from top left are Eden Espinosa, Cleavant Derricks, Ramona Keller, Karen Olivo and Kevin Anderson.