What bogs down this tale of teenage Bella (Kristen Stewart), her vampire beau Edward (Robert Pattinson) and werewolf buddy Jacob (Taylor Lautner) is the morose nature of Bella and Edward's romance. Though an improvement over the first Twilight film, this sequel (both based on Stephenie Meyer's best-selling books) drags and sputters, even in scenes meant to be infused with passion.

Pattinson is not given as much to do in this installment since he removes himself from Bella for her own protection. Bella spends an inordinate amount of time pining away. Unless it's a Ingmar Bergman film, watching an expressionless person stare out a window or trudge around alone in the woods is simply a drag.

Even while together early in the film, Edward and Bella spend a lot of their time staring intensely and brooding, arguing about whether she should "change," the apparent euphemism for becoming a vampire. They rarely seem to be enjoying each other's company. Being in love with the undead can be a grim undertaking.

Edward has a habit of making his entrances in dramatic slow-mo, unintentionally eliciting laughter. In contrast, when Jacob, a member of the local Quileute tribe, appears — often shirtless — his ultra-fit physique draws squeals from young female audience members. Even gloomy Bella comes out of her funk long enough to comment on his newly buff bod and cropped hair.

The scenes with Bella and Jacob are actually playful, a welcome relief from the lugubrious "love hurts" connection Bella shares with Edward.

As played by Lautner, Jacob has a spark in the film that wasn't as apparent on the page. Conversely, Edward was wittier and more intriguing in the book than as Pattinson plays him. His character is all about the piercing stare, and little else.

Once Jacob and his pals morph into teenage werewolves, the pace picks up. Then it dials down again when Bella, Edward and Edward's sister Alice (Ashley Greene) venture to the Italian hilltop town of Volterra. The intended suspense when they are confronted by evil vampire rulers never pans out. Michael Sheen, the crimson-eyed Aro, plays the character with more high-pitched giddiness than menace. Dakota Fanning has a small role as the innocent-looking Jane, who calmly tortures Edward with her mind.

Director Chris Weitz (The Golden Compass) has crafted a film with visual flair and polish, particularly in the action sequences of werewolves vs. vampires. Fortunately, he is more sparing with the tight close-ups and swirling shots that typified Twilight director Catherine Hardwicke's dizzying style. But there is a plodding quality to both movies.

The lovelorn Bella has little to recommend her as a heroine. She's sullen, self-absorbed and stubborn. That such a bland and passive character elicits the amorous devotion of both Edward and Jacob is rather mystifying. Almost as incomprehensible is the huge appeal of this series, beyond the obvious timeworn fascination with vampires and werewolves.

New Moon, the film version, does nothing to add depth to a shallow tale.

Enlarge AP/Summit Entertainment Kristen Stewart, left, plays Bella and Taylor Lautner plays werewolf friend Jacob in The Twilight Saga: New Moon.