The second adaptation of a John Green YA novel in as many years, “Paper Towns” eschews the tearjerker formula of “The Fault in Our Stars” in favor of a meandering coming-of-age tale that comes across as a nostalgia trip for John Hughes devotees. The novel’s publication actually predated that of “Faults” by a few years, and perhaps that’s why it feels like a less finished piece of work. An engaging cast and talented director–Jake Schreier, who made “Robot & Frank”–work hard to keep the movie afloat, but in the end the blandness does it in.

A prologue shows how young Quentin Jacobsen (Josiah Cerio) falls in love with Margo Spiegelman (Hannah Alligood) from the very moment he sees her moving in across the street of their Orlando suburb. They become fast childhood friends, but grow apart when Margo increasingly becomes part of the popular crowd and Quentin doesn’t. By the time they’re high school seniors—now played by Nat Wolff and Cara Delevingne—they barely ever speak, though he’s still obsessed with her.

That’s why he’s shocked one night when she knocks on his second-storey window asking for his help in taking revenge on her hunky boyfriend Jase (Griffin Freeman), who’s cheated on her with Becca (Caitlin Carber), and his jock buddy Chuck (R.J. Shearer), who helped his deception. They arrange for Jase to get caught literally with his pants down by Becca’s father, while denuding Chuck of one of his eyebrows. They also get back at Margo’s best friend Lacey (Halston Sage), who she believes knew about Jase’s infidelity and didn’t tell her, by encasing her car in plastic wrap.

After their parlous night’s adventures—which end with Margo taking him into a skyscraper, where they dance overlooking what she refers to as the “paper town” and its “paper people”—Quentin’s certain she and Margo will be a couple again, and just in time for prom! Instead she simply disappears—not her first time running way—and he determines to find her, enlisting his best pals—straight-arrow Radar (Justice Smith) and geeky Ben (Austin Abrams)—in the effort. In an oddly random fashion that’s only the most blatant way the story strains credulity, they find cryptic clues that suggest Margo’s gone off to a literal paper town—a fake one that cartographers insert on maps to foil plagiarizers—in upstate New York.

Before long Quentin, Radar, Ben, Lacey (whom Margo misjudged) and Radar’s girlfriend Angela (Jaz Sinclair) have climbed into the Jacobsen family van for the drive to Algoe, New York, during which Radar and Angela have their first night together and Ben and Lacey hook up as a very unlikely couple. When they arrive at the derelict barn that marks the spot, Margo isn’t there, and the others want to leave so they can get back for the prom; but Quentin insists on remaining. Will he find Margo, and what will happen if he does?

Fans may find fault with the changes from the book that the script indulges in, but though some of them add to the implausibility of the plot (which is pretty great to begin with), the major problems come straight from Green’s tome. The most important is the character of Margo. We’re supposed to care about her—and to believe that Quentin could feel so deeply about her. But at least as played by Delevingne, she comes across as flighty, self-absorbed and shallow (despite her collection of vinyl LPs and the copy of “Leaves of Grass” on her desk). It’s little wonder that when she runs off, her parents seem less distraught than relieved. Of course that’s ultimately the crux of Green’s point—that Quentin’s belief that she’s the miracle that will fulfill her life is the sort of childish notion one has to outgrow, and that you should learn to appreciate the good around you rather than long for some ideal of perfection. But it becomes a little annoying to watch Quentin take so long to realize something that’s apparent to us from the start.

On the other hand, Quentin might come across as a mite dense (a kind of Cameron who has to find his way without a Ferris to guide him), but the charming Wolff makes him more than tolerable, and the ingratiating Sage makes up somewhat for Delevingne’s oh-so-superior smugness. Even better are Smith, Sinclair and Adams. Some of the details added about uptight Radar are way too cutesy—a running gag about his parents’ obsessive collecting of Black Santas gets old fast, and another throwaway bit (involving a T-shirt emblazoned with an embarrassing decal) might seem a mite tasteless in view of current controversies—but he and Sinclair make a pleasant pair. Abrams, meanwhile, does for this film what Anthony Michael Hall did for the geek in “Sixteen Candles,” bringing a note of pathos to what might have been an obnoxious stereotype of horniness. The young actors playing Margo’s enemies do their nasty routines well enough, and technically the low-budget picture is okay, though the efforts of production designer Chris Spellman, set decorator Summer Eubanks and cinematographer David Lanzenberg to contrive a creepy feel for one location—an abandoned strip mall—fail signally. Ryan Lott’s music is negligible, too.

None of that will matter to Green’s legion of fans, however. “Paper Towns” may be paper-thin itself, but the target audience will doubtlessly embrace it, paving the way for still more adaptations of his books. And quite honestly one can think of far worse things than that for younger viewers.