YOUNG ADULT (R) Mavis Gary (Charlize Theron), a ghostwriter for a once-popular line of young-adult novels, is in a rut. She's miserable with her life, she can't finish the last book in the recently cancelled series, she's an alcoholic, and she's allergic to any semblance of honesty. When she finds out that her old high school boyfriend, Buddy Slade (Patrick Wilson), is a recent father, Mavis impulsively reacts to the news by returning to her small Minnesota town in an attempt to “rescue” Buddy from what Mavis believes is domestic hell. Back home, Mavis reluctantly hangs out with the nerdy Matt Freehauf (Patton Oswalt), a crippled old schoolmate to whom Mavis never paid attention when they were students, now serving as her confidant. Deluded in her mission to reignite her old love affair, Mavis zeroes in on Buddy and unleashes chaos.

There's a well-sold idea in Hollywood that all movies must implement a strong character arc for their protagonists, and for one with severe flaws, the arc has to end with some kind of redemption. Protagonists have to come to some sort of realization about their folly, and then we the audience can leave the theater believing we are all capable of change, even if it comes at a painful cost. American movies have long traded on that fallacy, time and again serving up myths of personal self-improvement as truth. It's a lie, of course, and Young Adult's screenwriter Diablo Cody (Juno, Jennifer's Body) thoroughly mangles the myth with a gleefulness that is nothing short of savage. This is a naturalistic comedy with a cruel acidity that director Billy Wilder would have approved of, though like Wilder's work, Cody’s story stays thankfully and surprisingly grounded in the all-too-human. Cody may have won the Oscar for her Juno script, but Young Adult is the best thing she's written so far. A lot of the movie's success, however, must also go to the performances by Theron and Oswalt. Theron won accolades for Monster and North Country, embedding herself under makeup and the characters' personalities. As Mavis, her beauty is undisguised, but Theron bravely embraces the character's inner ugliness with a gusto that male actors routinely get away with and actresses rarely attempt. Oswalt, too, delivers a painful yet nuanced performance as the moral heart of the picture. Viewers needing convenient dramatic resolutions will feel frustrated by Young Adult. Everyone else should enjoy the pain.