Marielle Heller’s Diary of a Teenage Girl is a directorial debut that thrives on silence. An unexpected and challenging comedy, the real genius of this movie is how much Heller’s script articulates explicitly, in intimately crafted lines, and how much it leaves lingering just under its breath.

The movie is a graphic departure from the conventions of its trope-heavy title. Fifteen-year-old Minnie, played by British actress Bel Powley in a breakout tour de force, lives with her family in the noisy technicolored sprawl of 1970s San Francisco. Diary is essentially the portrait of Minnie—a budding cartoonist and academically-challenged high schooler—in the moment she becomes aware of her sexuality. While a sexual awakening is perfectly suited to its milieu, and although at first the association of story and place feels obvious, even tired, Minnie’s perspective is so insistently personal and fresh, the movie feels purposeful from its disconcerting opening shots to its last unspeaking pan over the seaside.

Minnie lives with her free-spirit single mother, Charlotte (Kristen Wiig), who divorced Minnie’s father, a stiffly Freudian psychologist called Pascal (Christopher Meloni), in favor of a succession of newer models. The current boyfriend, Monroe (Alexander Skarsgard), is a clumsy, dozing pretty boy wrapped up in a lifestyle like Charlotte’s: he’s constantly cracking open a can of beer, making teasing, charming asides, or charting his future start-up fortunes.

Into the mix comes Minnie’s wide-eyed snooping little sister, Gretel (Abby Wait, in a role that feels more selective and minimized than it might have been), and Pascal, hovering pretentiously on the sidelines. Kimmie (Madeleine Waters), Minnie’s conventionally pretty best friend, alternatively leads and cautions Minnie as they both grapple with their respective “adult” lives.

The movie is based on the bestselling 2002 graphic novel—or perhaps, mix of novel and sketchbook?—by Phoebe Gloeckner, and while the work is based on details of the author/artist’s own life, she insists it isn’t a work of memoir. Rather it’s a story “‘about’ nothing,” an “encapsulated world,” as she calls it in her preface to the revised edition. The Minnie of Gloeckner’s book is meant to have a life of her own, distinct from a sense of autobiography; that burgeoning sense of Minnie’s personhood, our and her developing sense of herself, is the silent current running beneath the movie’s drama.

Minnie addresses her questions about what “normal” sexual desires are to her voice-recorded diary, in voiceover narration that overflows the diegetic logic of the screen and speaks, instead, to the audience. She has plenty of uncertainty, but plenty of excitement too, as she finds herself on the cusp of growing up—becoming her own autonomous person, as she sees it. But a silent gulf exists between her and the adults in her life, between her hopeful enthusiasm and the mystery of her mother and Monroe’s boisterous, free-wheeling, and obvious sexuality. Her small, private life—school and family—makes less and less sense to her, with all its wild new adult possibilities. Here is one of Heller’s most subtle interweavings: Minnie’s explicit cassette-diary commentary, composed of the worries she knows how to articulate, and, then, the audience’s sense of her situation’s tenuous underpinnings.

The story becomes knotted when Monroe takes up a secret, manipulative affair with fifteen-year-old Minnie. It’s a silent, gradual, drunken, and expressly physical relationship—and Heller communicates it so smoothly, so sympathetically, that it doesn’t fall into the trap of exploitative shock-value spectacle. The sense of taboo falls just out of the range of Minnie’s budding understanding of herself—and her enigmatic, hesitant sense of herself as an adult. But because Heller controls her subject matter well, because her characters are convincing and their voices energetic, the preoccupation with sex doesn’t overpower the sense of Minnie’s inner life. The movie wears a loud, obvious face; it intimates, more quietly, an inner language of Minnie’s awareness. She finds herself, apparently, able to have an influence on the world of grown-ups. Just as Minnie is powerless to fully understand what she wants to see as a romance, the movie is unable to fully articulate from her perspective how she should understand herself as an “adult” person.

The movie operates on layers of silence, layers of secrets. The secret of the relationship living in parallel to Minnie’s mother. The secret of Minnie’s own active inner life. Her private ambitions, her creative aspirations. While Minnie busily narrates the minutia of one relationship or another, she blatantly overlooks the visually obvious attentions of other characters toward her. Silently, the film weaves a story outside Minnie’s awareness, contextualizing and enriching her perspective.

And while the dialogue is used with beautiful precision, the spaces between it—small moments of contact, strained, casual, self-conscious, intimate—give breathing room to Minnie’s unconscious self-expression. More explicitly, Minnie’s imagination becomes briefly, dreamily visible on screen in the form of graphic novel-like animations, Powley’s eyes effectively speak volumes, belying her simplistic, endearingly juvenile voice over. I wonder what my body looks like; I wonder what he’s thinking about me. Sexuality itself is dealt with in often graphic terms, unsparingly direct. Minnie’s sexuality is articulated through the most explicit of the film’s languages: lewd daydreams, her cartoon imagination, and verbally in her cassette tape diary.

At the same time, concepts of sexuality are changing around her, in parks where women’s bodies are on display, in her house where her mother’s relationship to her boyfriends is very different than that of two decades before, in parties where drugs and queer sexuality are obvious and accessible. Amid all this shifting confusion, Minnie’s curiosity feels urgent. And that urgency, that shifting upheaval in how Minnie the Woman is able to interact with the world, is part of what clouds her sense of her relationship to Monroe. The tense uncertainty unfolds through the movie’s silences, rather than its dialogue. Minnie watches a braless jogger in the park. Minnie kisses a girl at a party. Minnie corrects her enthusiastic teenaged crush mid-intercourse. Alternatively absolutely confident or anxious for approval, she’s a wonderfully variable and convincing character who shines at the heart of the movie. We can hear the questions she asks herself under the surface of her misadventures, desperation, isolation. Am I important to him? Am I betraying myself? Do I know more, or less, about my own life than other people do?

Minnie does not read like a victim in her own story. She is not relegated to the level of someone who has been damaged and who now needs to heal from the harm inflicted by familial abuse. Her warped and clandestine status as a lover, a first love, a child, are aspects of who she senses herself to be. Even if silence, at the end of the film, masks whatever painful complications linger, the film rests on a masterful sense of cohesion. Everything leads forward.

The inescapable narrative similarity to Lolita is perhaps the most explicit trope underlying the film—again, silently. The film doesn’t let its silence stretch so far as to allow for a misinterpretation of its plot as a reimagining of that famous narrative, recast as a love story. Don’t you feel like he’s taking advantage of you? Kimmie asks, immediately. Minnie’s fumbling response is absolutely earnest but somewhat uncertain: It’s different, it must be different. The audience hears the yawning disconnect; it’s in the fumbling silence. Minnie doesn’t lose stature within her own story though: she’s still the frank, eager, forward-momentum protagonist we’ve come to understand. But she doesn’t hear one loud and obvious fact of her own story, embedded in Monroe’s manipulative reprimands: sexuality is one thing, but the power dynamics between people are as prevailing and unspoken as the movie’s silence. And yet, that dynamic doesn’t make her powerless. It only means that her role—and the way she situates herself as an Adult Person in her Adult World—cannot be seen inside a silent vacuum, where large truths go unspoken for the sake of comfort. Recognized, if not articulated, Minnie’s self-realization is wonderfully, inescapably tangible as Heller’s bold character portrait brings her into focus.