Holed up in a bar in the wee small hours of the morning, self-pitying Raoul (Joseph Millson) is having a “One for My Baby” moment. “The rush that music brings,” he sings, “I can’t deliver.” The trouble with “Love Never Dies” is that while a couple of melodies deliver, the show doesn’t. Andrew Lloyd Webber’s sequel to “The Phantom of the Opera” wants to be a tragic romance, but it’s simply torpid. Only a radical rewrite will give it even the remotest chance of emulating its predecessor. Skedded for a Nov. 11 Gotham opening, it has eight months in which to improve.

The original “Phantom” plot is famously less than watertight. But designer Maria Bjornson’s seductive gothic visuals so enhance the central romance that it creates the illusion of coherence, not least because its action is confined to one place: the Paris Opera. “Love Never Dies” is, in every sense, too diffuse.

Once again, there is a time-slip framing device. But where the “Phantom” opening had action and tension — it’s an auction, what is this mysterious chandelier, who’s buying that music box and why? — this show is content merely to dress Liz Robertson’s one-note Madame Giry as Judith Anderson’s Mrs. Danvers and have her spout exposition. Through her declaiming, we learn about the 1907 Coney Island location and its entertainment wonder, the fun palace that is Phantasma. No prizes for guessing its impresario.

Ten years on from his mysterious disappearance, our (anti-)hero (Ramin Karimloo) has lured unsuspecting Christine (Sierra Boggess) to his lavish theater where she will once again sing his music. Imagine her surprise when, having arrived with furious and selfish husband Raoul and 10-year-old son — do the math — she discovers her composer is you know who.

At this already late point, the scenario suggests possibilities for building and driving tension. Whose child is it? Will she fall in love again? Will she sing the show’s title song? That you don’t need a crystal ball to guess the answers is the fault of the fatally tension-free book, which poses questions but fails to dramatize them.

Characters emote but don’t develop. The Phantom is desperate, Raoul is hate-filled, Christine is searching for love, Phantasma star Meg Jiry (Summer Strallen) is jealous of Christine, Madame Giry is bitter. It’s like watching actors play the treatment rather than the script.

That’s particularly ruinous in the distended final sequence. Having watched a character toy with a gun in an earlier sequence, we’re primed, but shouldn’t a character’s death engender more than puzzlement as to why the killer remains onstage sobbing throughout the pained reprises going on around them?

When spirits do sometimes rise, it’s thanks to the all-new score. Half-masked Karimloo stalks about attempting to look fierce, but doubts vanish when he launches into a full-throated performance of Puccini-esque, slow-build-to-triumph song ” ‘Til I Hear You Sing,” the best number Lloyd Webber has written for a man since “The Music of the Night.”

Boggess also seizes her operatic soprano moment — “Love Never Dies,” which first surfaced onstage in Lloyd Webber’s 2000 flop “The Beautiful Game” — with similar aplomb. When she lets go with it, you realize what potential has been missed elsewhere.

Armed with David Cullen and Lloyd Webber’s plush orchestrations for a string-based 21-piece band, conductor David Charles Abell makes the grand opening Coney Island Waltz overture one of the evening’s standouts. Yet in a tuner where songs should take precedence, that’s something of an indictment of Glenn Slater’s serviceable but unmemorable lyrics.

The oddest thing about Jack O’Brien’s production is its old-fashioned feel. Jon Driscoll supplies nicely poetic, location-setting video projections, but they are often splashed over scrims flown in to cover scene changes.

And while many of Bob Crowley’s sets achieve art-nouveau majesty, others, like Christine’s dressing room — a table looking lost against stage-wide drapes — suggest unsolved problems. There’s no enveloping mood and the entire production design, united by Paule Constable’s beautifully atmospheric lighting, strains to lend fluidity and momentum to the piece.

At the moment, watching the sequel only makes you appreciate the achievement of the original.

Love Never Dies

Adelphi Theater; 1,469 seats; £67.50 top

  • Production: A Really Useful Group presentation of a musical in two acts, music by Andrew Lloyd Webber, lyrics by Glenn Slater, book by Lloyd Webber and Ben Elton with Glenn Slater and Frederick Forsyth. Directed by Jack O'Brien. Musical direction, David Charles Abell. Choreography, Jerry Mitchell.
  • Crew: Sets and costumes, Bob Crowley; lighting, Paule Constable; projections, Jon Driscoll; sound, Mick Potter, music supervisor; Simon Lee; orchestrations, David Cullen and Lloyd Webber; special effects, Scott Penrose; production stage manager, Jo Miles. Opened, reviewed Mar. 9, 2010. Running time: 2 HOURS, 30 MIN.
  • Cast: The Phantom - Ramin Karimloo Christine Daaé - Sierra Boggess Raoul - Joseph Millson Madame Giry - Liz Robertson Meg Giry - Summer Strallen Fleck - Niamh Perry Squelch - Adam Pearce Gangle - Jami Reid-Quarrell Gustave - Jack Blass, Harry Child, Tyler Fagan, Alexander Hockaday, Richard Linnell, Charlie Manton, Kaisun Raj With: Derek Andrews, Dean Chisnall, Lucie Downer, Paul Farrell, Charlene Ford, Celia Graham, Simon Ray Harvey, Jack Horner, Erin Anna Jameson, Pip Jordan, Jessica Kirton, Louise Madison, Janet Mooney, Colette Morrow, Tam Mutu, Ashley Nottingham, Tom Oakley, Mark Skipper, Lucy van Gasse, Annette Yeo. Musical numbers: Act 1: "Prologue," "The Coney Island Waltz," "Heaven by the Sea," "Only for Him/Only for You," "The Aerie," " 'Til I Hear You Sing," "Are You Ready to Begin?," "Look With Your Heart," "Beneath a Moonless Sky," "Once Upon Another Time," "Dear Old Friend," "Beautiful," "The Beauty Underneath." Act 2: "Entr'acte," "Why Does She Love Me?," "Devil Take the Hindmost," "Heaven by the Sea (Reprise)," "Ladies ... Gents!/The Coney Island Waltz (Reprise)," "Bathing Beauty," "Before the Performance," "Devil Take the Hindmost (Quartet)," "Love Never Dies," "Ah Christine!," "Gustave! Gustave! ... ," "Please Miss Giry, I Want To Go Back ... "
  • Music By: