Broadway musicals don’t seem to know what to do with their literary heroines lately. Jo March was reduced to a spunky tomboy in “Little Woman” last year; now it’s Marian Holcomb’s turn.

Marian, the supremely resourceful woman at the center of Wilkie Collins’s 1860 pageturner “The Woman in White,” has been downgraded in Andrew Lloyd Webber’s retelling to a squealing girl with a crush who does her sleuthing by flashing some skin. As impressive as Maria Friedman is in the role – and she is every bit equal to the hype generated over two decades of acclaimed Lon don performances – her efforts are all the more amazing in light of the retrograde caricature she has been saddled with.

“The Woman in White” is not an untouchable text. A twisty tale of lunatic asylums, squandered fortunes, scheming servants, dark family secrets, the titular specter, and a pair of hissable villains, it hinges on one questionable plot leap after another. But Mr. Webber, who mined similar material with world beating success in “Phantom of the Opera,” here delivers a turgid, undercooked bore, a parade of interchangeable megaballads and telegraphed scares distinguished only by a misguided visual scheme and the sight of West End favorite Michael Ball in a fat suit, playing with live mice.

“Phantom” drew heavily from its operatic surroundings to undergird the melodies. Beyond a few unmemorable, faux-rustic chorus numbers, Mr. Webber’s latest score is devoid of any such anchor, and the result is an undifferentiated wash of semi-catchy solos and meandering recitations. Are songs like “Trying Not To Notice” and “If I Could Only Dream This World Away” pleasant to listen to? Sure. Is there a single note in them that grounds the listener in any particular time or place, let alone the appropriate one? No.

The score’s problems go deeper,as evidenced by the Act I song “I Believe My Heart.” (The next line is sometimes “It believes in you” and sometimes “How can it be wrong,” which says pretty much everything you need to know about David Zippel’s lyrics.) The song is introduced as part of the courtship between Marian’s willowy half-sister, Laura (Jill Paice, who looks and sounds lovely), and their strapping drawing instructor,Walter (Adam Brazier, airlifted in from Pop Opera Central Casting).

Fair enough. But then Laura gets married off to the villainous Sir Percival Glyde (Ron Bohmer, who walks away with every scene he’s in). When she returns from her honeymoon despondent and covered in bruises, the orchestra kicks into a lush reprise of … “I Believe My Heart.” What does that melody have to do with anything happening on stage? Beyond sounding pretty, the motif has no reason for existing there.

A similar confusion surrounds Count Fosco (Mr. Ball), Sir Percival’s corpulent Italian partner in crime. Collins’s novel plays out as a continual battle of wits between Marian and Fosco, with the heroic Walter, the delicate Laura, the spooky Anne Catherick (played here by a suitably unearthly Angela Christian), and the dastardly Percival each generating a few plot points.

But Charlotte Jones’s libretto diminishes the roles of both Marian and Fosco so drastically that a tired-sounding Mr. Ball is left with nothing besides a pair of comic would-be showstoppers. And “By Jeeves” notwithstanding, the number of successful comic songs by Mr. Webber can be counted on one hand.These are not among them.

One’s attention drifts queasily from the thudding lyrics and the drifting English accents to the Marquis Theatre’s massive moving screens, which display William Dudley’s much ballyhooed animated projections in lieu of a traditional set. These allegedly revolutionary images of forests, billiards rooms, churches, and the like are – well, they’re terrible.

The projections look like they came from one of those straight-to-video Disney sequels – “Niece of Aladdin” and that sort of thing. Coordinating them on a half-dozen moving platforms must be difficult, but if this is the best they can do, the technology should be mothballed.

The lack of sets also puts the actors in a bind. You know that 16-bar pause in pop-opera ballads, the one before the singer returns in a higher key and several decibels louder? Those are tough to stage under any circumstances, but poor Ms. Friedman is forced to walk in circles around the stage, literally wringing her hands. She has to contend with a barrage of unconvincing graphics pinwheeling behind her. (Well behind her: Director Trevor Nunn, who may have to give back his “Nicholas Nickleby” and “Les Miserables” Tony Awards after this one, plunks his soloists down front and center for just about every number.)

With the exception of strong work from Ms. Paice and especially Mr. Bohmer in negligible roles,the only reason to see “The Woman in White” is Ms. Friedman. She handles the tiresome material with class and emotional integrity, and her husky yet plaintive alto gives an actual spine to her central ballad,”All for Laura.” Broadway shouldn’t have had to wait 20 years to get her, and Ms. Friedman shouldn’t have had to settle for this clogged bit of tedium to get here. She deserves better.

So do we.

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