Minnie desperately wants to be loved. But like 15-year-old girls the world over, she feels unlovable.

   This leads her into the desperate acts that are the subject of The Diary of a Teenage Girl, a provocative first film from writer/director Marielle Heller. Based on Phoebe Gloeckner’s semi-autobiographical graphic novel, it forces us to watch as Minnie embarks on a creepy journey of self-discovery.

   How creepy? Read on.

   Living in San Francisco in the 1970s, Minnie (Bel Powley) confesses to the tape recorder that serves as her diary that she was an “ugly child” and hasn’t improved since then. Adding more baggage to her inferiority complex, she lives in the shadow of Charlotte (Kristen Wiig), a beautiful but distant single mom who has no trouble winning men’s admiration.

   So when Charlotte’s boyfriend, Monroe (Alexander Skarsgard), shows an interest in Minnie, the girl eagerly coaxes him into a full-blown affair. Who knows, she asks herself, whether she’ll ever have another opportunity.

   Minnie’s relationship with Monroe shrouds the movie in an atmosphere of disturbing amorality much like that of a popular stage play, Paula Vogel’s How I Learned to Drive. What makes it particularly challenging is that Monroe is not depicted as out-and-out monster.

   As he’s brilliantly played by Skarsgard, Monroe is a weak-willed opportunist rather than a cynical predator. He knows he shouldn’t be sleeping with his girlfriend’s underage daughter, but he can’t help himself. He even likes the girl—maybe more than he’s willing to admit.

   Just as brilliant is newcomer Powley’s portrayal of Minnie, whose aching need for affection overrules any pangs of conscience she might be suffering for sleeping with her mom’s boyfriend. “Is this what it feels like when somebody loves you?” she asks her diary after losing her virginity to Monroe.

   Though actually in her early 20s, Powley perfectly captures the awkwardness and self-doubt of the average teenage girl. Of course, parents in the audience will hope Minnie is less average in terms of her actions. After hooking up with Monroe, she goes on to other experimentation in the areas of sex and drugs.

   And where is her mother during all of this? Preoccupied by alcohol, drugs and partying, Charlotte seems almost willfully oblivious to her daughter’s traumas. Emotionally speaking, this mom is simply not around.

   Though it’s filled with far more sex, drugs and nudity than the average teen comedy, The Diary of a Teenage Girl can hardly be called exploitative. Screenwriter/director Heller handles the tricky material with care and sensitivity.

   Oddly, the creepiest scenes have nothing to do with underage sex. Instead, they involve Minnie, younger sister Gretel (Abby Wait) and Charlotte’s manipulative ex, Pascal, played by a very un-Law & Order-like Christopher Meloni. 

   Thankfully, Minnie’s story is not as bleak as it might sound. Heller lightens the mood with moments of comedy and flashes of hope.

   As talented as she is precocious, Minnie becomes increasingly preoccupied by art—her own and that of artists she admires. We know this because Heller and cinematographer Brandon Trost often incorporate her doodlings into the live action. At times, Minnie even carries on deep conversations with her favorite cartoon character.

   Such moments add welcome touches of whimsy and optimism to a story that otherwise could be downright depressing.

   Rating: 4 stars (out of 5)

   The Diary of a Teenage Girl, rated R, is now showing at local theaters, including the Drexel Theatre, Gateway Film Center, Lennox Town Center 24 and Easton Town Center 30.