The “Twilight” movies, bad as they were, became a cultural phenomenon, and Stephanie Meyer’s fans—and the producers of the film—are obviously hoping that with “The Host,” the new film from one of her other books, lightning will strike twice. After all, it includes another romantic triangle composed of attractive young people. But in this case the triangle actually has four sides, since the girl in question has been possessed by an extraterrestrial entity with which she shares her body. Among the complications that ensue, one boy remains in love with the original human host while the other shows increasing interest in the non-human personality in the equation. Unfortunately, in attempting to replicate the formula that made her previous trilogy such a success both on the page and the screen while giving it a new twist, Meyer has concocted an extremely silly story made worse by Andrew Niccol’s ponderous, self-important adaptation of it.

The premise is that earth has been invaded by beings that travel the cosmos, hopping from planet to planet to take over their inhabitants and turn them all into peaceful, docile individuals who will form a harmonious society that can endure after they depart for another locale to continue their beneficial work. On earth, however, they encounter resistance from some who are intent on maintaining their own personas, warts and all. So some of the invaders become Seekers, assigned to track down the troublemakers and bring them into the fold.

One such unincorporated human is Melanie Stryder (Saoirse Ronan), who’s captured by the Seekers and has one of their number implanted in her. But Melanie’s a strong-willed gal, and her consciousness survives within. Moreover, her possessor is a wise, beneficent being that calls itself the Wanderer (and is later christened Wanda) and proves remarkably solicitous. Together—how could it be otherwise?—they make their way back to Melanie’s rebel community, which lives underground in a network of caves beneath the New Mexico desert. It’s led by sagacious Uncle Jeb (bearded William Hurt), and includes Melanie’s kid brother Jamie (Chandler Canterbury) and her two ardent admirers, Ian (Jack Able) and Jared (Max Irons).

Disputes arise almost immediately over whether the ‘new’ Melanie can be trusted, and how to deal with her. It certainly doesn’t help that she’s being pursued by a particularly determined Seeker (Diane Kruger), who’s intent on finding her refuge and is happy to lead the efforts to capture other members of the community when they venture out for needed supplies. A particularly dicey situation occurs when Jamie is injured and desperately needs medication. Meyer provides a happy ending of sorts—several of them, in fact—but still leaves room for a sequel or two, if she ever gets around to writing them.

“The Host” is basically a friendlier variant on the old Pod People scenario, and Niccol, who has specialized in cerebral (if deeply flawed) science-fiction stories like “Gattaca” and “In Time,” and he obviously wants to use it to say something serious about identity, free will and conformity—or, in the most general terms, the possibility of coexistence. But he’s hobbled by Meyer’s casting of these themes in “Twilight”-like romantic terms, and never finds a proper pace and tone for what is, after all, a pretty goofy, hackneyed narrative. Apart from the requisite action sequences—chases in futuristic cars, for instance—his approach is to present everything at a nearly funereal pace, with most of the dialogue delivered so slowly and portentously that it almost sounds as though it were being read phonetically. (A sequence that’s meant to generate tension, when Melanie/Wanda ventures to an alien clinic to retrieve some needed medicine, is boring instead.) This has a dulling effect that’s particularly noticeable in the best actors—Ronan, who’s stuck reciting the pedestrian narration as well as the almost comical conversations with herself (the sort one might recall from “Breaking the Waves”), and Hurt, who seems to be sleepwalking through the picture. Abel and Irons, meanwhile, prove handsome but bland suitors, while Canterbury seems rather lost and hesitant throughout.

Even visually “The Host” is a disappointment. Though the desert locations are striking and nicely caught in Roberto Schaeffer’s widescreen cinematography, the design of the film in terms of buildings, clothing and vehicles is for the most part curiously uninteresting.

The result is a movie that resembles, in its look and manner, neither “Twilight” nor “Gattaca” so much as an episode the old TV series “The Outer Limits” (the mediocre Canadian reboot, not the great sixties original). There’s actually the seed of an idea to “The Host,” but Meyer drowned it with her propensity for the clichés of the “young adult” genre, and now Niccol has embalmed it with his lethargic, heavy-handed treatment.