Adam Rapp is a prolific, much-honored writer of plays and young adult novels. He draws on both genres in The Edge of Our Bodies, a hit from the 2011 Humana Festival of New American Plays that’s now getting its South Florida premiere at Plantation’s Mosaic Theatre.

The play is an almost-solo show, a slice-of-young-life story told by 16-year-old Bernadette, a student at an upper crust New England school. Rapp throws in snippets of dialogue from Jean Genet’s The Maids (Bernadette is in a school production of the play), and near the end of the show reality intrudes in the form of a janitor who has come to strike the set.

But mostly, The Edge of Our Bodies consists of articulate, observant Bernadette reading aloud from her journal, sharing the story of her train trip to Brooklyn to tell her 19-year-old boyfriend that she’s pregnant.

That’s dramatic news related in what seems, initially, a static format. Lexi Langs, an experienced young actress who is working toward her degree at New York University’s Tisch School of the Arts, at first plays Bernadette as a slightly nervous, quietly introspective girl who barely manages to raise her eyes from the pages of her journal. But Langs and director Margaret M. Ledford start small for a reason.

They aim to surprise the audience with the different facets of Bernadette’s personality, with the way she can be honest one minute, a fabulist the next. They want the shocks, heartbreak and dangerous experiences of her life to register hard. They want to cast a spell. And they do.

In creating Bernadette, Rapp captures the push-pull of teen life, the pendulum swinging from the safety of the familiar to the illicit thrills of experimenting with adulthood. Langs seems sweet, empathetic, a kind of anxious innocent as Bernadette talks with her absent boyfriend’s father, a man whose battle with cancer is nearly over. But then “Bernie” travels into Manhattan, tries on a different persona and has a raw, vulgar sexual experience with a much-older guy.

Langs also slips into bits of The Maids, acting in the exaggerated way an unpolished 16-year-old might, with Rapp taking us into Genet’s world in a way that is more confusing than resonantly enlightening. When the school maintenance man (Jim Gibbons) finally appears, lighting designer Suzanne M. Jones floods the space with bright, unforgiving light as reality abruptly invades Bernadette’s world of remembrance, disappointment and make-believe.

The Edge of Our Bodies is vividly written, provocative, shocking, reflective. Thanks to the intricately collaborative work of Langs and Ledford, Mosaic’s production is absorbing, infused with wintry melancholy and, like a sudden snowfall, delicately beautiful.