Caryn Waechter’s debut feature has a distinguished pedigree: it was adapted by Marilyn Fu from a short story by Pulitzer Prize-winning author Stephen Millhauser. But while “The Sisterhood of Night” certainly has the ambition to be a poetic treatment of the angst that fills the lives of many teen girls (and its sometimes uncomfortable ramifications), in the end the film, while very nicely fashioned, winds up as an oddly prosaic cautionary tale dressed up in quasi-literary duds. The inspiration might be the Salem Witch Trials, but bringing the message they carry into the age of cyberbullying in the blogosphere gives things the air of an upscale afterschool special.

The setting is the small New York town of Kingston, where Mary Warren (Georgie Henley), a rebellious semi-goth high-schooler, undermines the drama audition of Emily Parris (Kara Hayward), a nervous sort who retaliates by stealing Mary’s phone and printing all her texts on the blog she’s anxious to expand. Mary responds not by retaliating via social media, but instead by going offline entirely—and recruiting select girls for a secret sisterhood that meets periodically in the woods at night. Her initial choices are Lavinia Hall (Olivia DeJonge) and Catherine Huang (Willa Cuthrell)—the one distraught over her parents’ recent divorce, the other worried about her ill mother—and in time she’ll add others to the roster; but she pointedly excludes Emily, who’s desperate for acceptance at all costs.

The slight leads Emily to follow the girls into the woods and then claim that the sisterhood is a sinister cult, given to strange nocturnal rituals with a distinctly sexual edge. The scandalous revelations cause widespread concern among parents, and will eventually have unfortunate professional ramifications for Gordy Gambhir (Kal Penn), the campus guidance counselor who tries to get at the truth (and serves as a narrator for us). But they have a positive effect on Emily’s blog, which becomes a magnet for young girls who claim to have been sexually abused and want to share their stories. They also win her support from some classmates, who falsely attest that they too were objects of the cult’s malevolent practices. Sarah (Morgan Turner), one of Emily’s more obnoxious followers, induces Travis (Deema Aitken), a cute guy fragile Lavinia is infatuated with, to induce her into the woods on Halloween night, where they humiliate her and post video of the altercation on the web. A tragic aftermath induces Emily to confess her lie, Mary to reveal what the sisterhood is all about, and the two to join in an expression of sisterly comradeship.

For the most part Fu and Waechter take this scenario very seriously, with only Penn on hand to add some mild levity to the proceedings with his wry delivery and engaging air. But while the young cast—especially Henley, who’s able to express an almost scarily intense attitude while maintaining an undercurrent of vulnerability—are almost uniformly excellent (the exceptions being Hayward and Turner, who can’t shake an amateurish feel), the plot often comes across as scattered. There’s a subplot involving Mary’s relationship to Jeff (Evan Kuzma), a pleasant classmate with a bent for photography; but nothing comes of it. And Emily’s entire turnaround comes across as a literary conceit rather than a plausible outcome. (Her mother Sue, played as a religious zealot by Jessica Hecht, is also drawn rather broadly, as is Lavinia’s hysterical mother Rose, played by Laura Fraser.)

In portraying the sisterhood’s activities, moreover, Waechter strives for a level of strange beauty she never achieves. Watching Mary and her cohorts gamboling about in flowing robes has about the same effect that the springtime activities of the residents of Sommerisle did in “The Wicker Man”—less enthralling than slightly absurd.

Still, in comparison to other films about teens trying to cope with the pressures of school and home, “The Sisterhood of Night” is notable for its ambition and refusal to resort to easy tropes. If it doesn’t quite surmount all the obstacles inherent in the genre, at least it tries.