Margo (Cara Delevingne) and Quentin (Nat Wolff) share an intimate moment during an all-night adventure in “Paper Towns.” (Michael Tackett/Twentieth Century Fox)

A low-key vibe is both the greatest strength and the greatest weakness of “Paper Towns,” Jake Schreier’s self-consciously modest adaptation of John Green’s 2008 novel. In case you’ve forgotten, Green also wrote “The Fault in Our Stars,” the movie version of which was well on its way to becoming a huge hit this time last summer. Although the low-stakes mystery that propels “Paper Towns” has little of that earlier film’s emotional pull — courtesy of two charismatic teens with cancer — this gentle coming-of-age story has its winning qualities. If it’s a bit dull, and too dependent on a what-I-learned voice-over to make its points, it can still be applauded for resisting the temptation to overreach.

The self-effacing ethic of “Paper Towns” is perfectly embodied in Nat Wolff, who had a supporting role in “The Fault in Our Stars.” Here, the young actor comes into his own as a leading man, reminiscent of a “Graduate”-era Dustin Hoffman.

Wolff plays Quentin, a high school senior who for the past decade has harbored a crush on his across-the-street neighbor Margo (Cara Delevingne), who was once his best friend but who now shrugs past him in the school hallway with heedless indifference. While Quentin hangs out with slightly nerdy band-practice buddies Ben (Austin Abrams) and Radar (Justice Smith), Margo runs with a faster, more sophisticated crowd.

A shy high school boy embarks on a mission to find the missing girl next door who has stolen his heart. (  / 20th Century Fox)

A mildly notorious character in their community outside Orlando, Margo is also practiced at burnishing the stories that have made her such a captivating enigma. She enjoys being talked about, even as she longs to escape the suburban torpor for more adventurous climes. When Margo disappears one day, after roping Quentin into one last epic night of creative mayhem waged against her perceived enemies, he besottedly comes to believe that she secretly wants to be found — by him and him only. Enlisting Ben and Radar, he sets out to discover her whereabouts and bring her home.

Quentin is studying “Moby Dick” in school, a helpful source of subtext for viewers who might miss the finer points of “Paper Towns.” But in chronicling a teenager’s first experience of obsession, projection and romantic yearning, this sincere, understated drama is at least more convincing than the more stylized “Me and Earl and the Dying Girl.” An icky running gag in which Ben lusts after Quentin’s mom notwithstanding, “Paper Towns” has been tastefully made and features appealing performances from its stars. Wolff possesses a soulful, expressive quietude that fits Quentin’s careful, observant nature, while the raspy-voiced Delevingne banishes all doubt whether, when Margo goes on the lam, she’ll land anywhere but on a flashbulb-bathed Manhattan catwalk.

The supporting players are good too, especially Smith, who delivers the film’s best jokes with terrific deadpan timing. A carefully planted cameo midway through the film is sure to elicit delighted gasps and giggles when it shows up. At that point, “Paper Towns” has turned into a road picture/teen romp — raising questions about why, if Quentin and his friends are just a few weeks away from graduation, it’s already autumn on the East Coast — and the true moral of the story is taking shape.

Younger viewers may not see the movie’s ending as particularly happy. Still, it’s nearly impossible to resist Green’s cheering if perfunctory message about the importance of friendship, identity and the willingness to examine our most cherished wishful thinking — even at the ripe and restless age of 18.

PG-13. At area theaters. Contains some coarse language, drinking, sexuality and partial nudity, all involving teens. 106 minutes.