The second movie in “The Twilight Saga,” called “New Moon,” is every bit as good as the first. That’s not intended as a compliment, because it means it’s also every bit as bad.

This installment in the hugely popular series of books by Stephanie Meyer declares itself upfront as a riff on “Romeo and Juliet,” but one may feel that in this case the tragedy lies in the fact that the lovers survive. What little plot there is involves pale, perpetually glum vegan vampire Edward Cullen (Robert Pattinson, looking persistently constipated) leaving little Forks, Washington, after deciding that his relationship with high school sweetie Bella Swan (Kristen Stewart) is endangering her. (That seems obvious when one of his brood nearly sucks her dry after glimpsing the blood dripping from a cut she’s suffered. It’s too bad that no one’s in a position to say “I never drink…wine” at that point.) He leaves no forwarding address.

Bella’s devastated, suffering terrible nightmares of withdrawal from her anemic paramour, but her old Indian pal, Jake (buffed-up Taylor Lautner), who’s always been infatuated with her, takes up the slack, agreeing to help her refurbish a couple of old motorcycles. But she has an ulterior motive: she’s discovered that at moments when her life’s in jeopardy, an ethereal Edward shows up as a vaporous image to warn her off. He’s still acting as her protector, even if after the danger’s passed he’s off as a puff of beautiful smoke.

Curiously, though Edward appears when Bella’s driving too fast or stupidly decides to go off with a creep on his cycle (at times like that one wants to re-christen her “Dumbella”) apparently doesn’t notice that she’s being stalked by some of his old blood-sucking enemies, including red-haired Victoria (Rachelle Lefevre). Happily Jake intervenes on her behalf; he has, you see, suddenly morphed into a werewolf (or shape-shifter, actually)—it’s a genetic thing, as he helpfully explains—and is now running with a vampire-hating pack, and he’s protective of Bella, too. But she keeps him at paw’s length, still pining away for Edward.

Edward, meanwhile, has come to believe that Bella’s dead, and in true Romeo fashion goes off to the Volturi, an Italian-based coven of powerful undead, to ask them to kill him. Fortunately (or not, depending on your point of view), Bella’s been informed of his intention by his sister Alice (Ashley Greene), and rushes across the globe to save him, last-minute style. And the movie ends with the two together again and Bella again insisting that Edward should “turn” her so they can remain so forever. His answer, as befitting something with more sequels to come, is qualified.

This romantic inter-species triangle is presented with such silly solemnity that it will take a strong person not to guffaw openly at it. Of the three characters involved, Bella comes across as a dismally dim bulb (she keeps noting that she feels as though she has “a hole in her chest,” but from the way she asks you might think it was actually in her head), and Edward’s pose of pained angst seems like a bad James Dean routine. Only Jake, who can occasionally crack a joke—if not a very good one, since Melissa Rosenberg’s script seems capable of only jejune one-liners—has any spark at all, and Lautner gives him a likable virility, though having him and his buddies always running about shirtless to show off their biceps is proof that the makers are just pandering to girls drooling after beefcake (after all, when they transform into wolves, their pants suddenly disappear, too). By contrast, Pattinson’s gloomy persona is even more tiresome this time around—you may find yourself pleased that he’s gone for so much of the picture—and Stewart, though she emotes a lot, never gets beyond high-school level dramatics.

The supporting cast provides only a few amusing exceptions to the overall downbeat atmosphere. Billy Burke is again pleasantly loose as Bella’s uncomprehending dad, and Graham Greene offers some whimsical moments as his Indian pal. Best of all is Michael Sheen, who shows up as the head of the Volturi and sends everything up with a mincing, prancing routine worthy of Liberace. He easily steals what little show there is by giving u a little vaudeville patter in the midst of the melodramatic twaddle that makes up the rest of the movie.

“New Moon” has a new director, Chris Weitz, as replacement for Catherine Hardwicke. The change doesn’t amount to much, since he proves a no more apt choice here than he did for “The Golden Compass.” The intimate scenes are pretty dreary, and the bigger action moments indifferently staged and shot. Working with cinematographer Javier Aguirresarobe, he manages only one really imaginative moment—a circular pan around Bella showing the passage of the seasons as she sits, sunk deep in depression, in her bedroom. Otherwise the lensing is pretty pedestrian, using the same drab color palette as Eliott Davis’ in the first picture. (Everything looks as though it were shot through sunglasses.) The special effects are adequate, but nothing special. And Alexandre Desplat’s score is a serious disappointing, considering the source; the tooting woodwinds running up and down scales during the romantic sequences are particularly annoying. But then, the picture can’t have provided much inspiration.

None of this, of course, will matter a whit to “Twilight” devotees—the young girls and not-so-young women who repeatedly squealed in delight at the preview screening whenever Lautner strode by sans shirt or Pattinson emitted one of his soulful sighs. But to anybody, else, “New Moon” will be nothing more than a lugubrious Harlequin romance with fangs and paws instead of bosoms and bodices.