If "The Wackness" is marketed or gets labeled as a "stoner comedy" in the vein of the "Harold and Kumar" and "Cheech and Chong" films, it will be an unwarranted classification that woefully misses the point. Yes, there is a lot of pot-smoking throughout, but it acts as mere window-dressing to the larger story that writer-director Jonathan Levine (whose first film, the acclaimed "All the Boys Love Mandy Lane," is still awaiting release) wishes to tell. A part-gritty, part-quixotic coming-of-age drama with a nostalgic tone that will particularly grab viewers who were teenagers in the mid-1990s (like myself), the picture doesn't exactly reinvent the genre, but it is an absorbing and affecting entry all the same.

It's the summer of 1994 in New York City, and Luke Shapiro (Josh Peck) has just graduated from high school. An outsider with few friends and a stressful home life—his parents (Talia Balsam and David Wohl) argue and fight constantly—Luke uses an ice vending front to sell weed on the streets. When he's not doing that or brooding about his uneventful pre-college existence, he attends private counseling with bong-wielding psychiatrist Dr. Jeffrey Squires (Ben Kingsley), one of his top clients. Luke, who prays his life will get better with age, and Squires, who desperately longs for the youthful days Luke is currently in the midst of, find a connection in the middle and become unlikely confidantes. As the sweltering months pass by, both men will be faced with some life-defining decisions—for Luke, to romantically pursue Squires' stepdaughter, Stephanie (Olivia Thirlby), with the knowledge that he's bound to get hurt, and for Squires, to finally face the dissolution of his icy marriage to Kristin (Famke Janssen).

Winner of the Audience Award at 2008's Sundance Film Festival, "The Wackness" is an affectionately crafted slice-of-life. Tough, touching and sometimes funny in an unforced way, the film wisely does not overidealize Luke's rite of passage. Nonetheless, writer-director Jonathan Levine still finds a sort of magic in his lead character's bumbling, alternately joyous and upsetting path toward unabashedly falling in love for the first time and ultimately accepting that life isn't always going to be the bed of roses he thinks it should be.

A know-it-all kid on the verge of adulthood, Luke meets his match—or is it perfect opposite?—in Dr. Jeffrey Squires, an aging shrink who envies Luke's adolescence and wants desperately to have his own back. Although Squires advises Luke to go for it with the girl he has a crush on, he is not at all happy when he finds out that that certain someone is his own stepdaughter. As these two protagonists awkwardly attempt, so to speak, to grab life by the balls, the film moves in some interesting directions and retains an appreciably naturalistic tone. Not all of the plot threads are entirely surprising—it's pretty clear that Stephanie is simply biding her time with Luke until her own friends return from summer vacation—but it is in the treatment of these oft-trodden conventions that the picture rings true. Luke's final scene with Stephanie is unexpectedly powerful in its simplicity and beauty—a heartbreaking moment in Luke's life that, by this time, he has learned to embrace.

"The Wackness" should mark Josh Peck's breakthrough role in terms of leaving his child star status behind (he is best-known for 2004's "Mean Creek" and Nickelodeon's "Drake & Josh") and becoming a formidable adult actor. He is nothing less than transcendent as Luke, a young man who has always stood from the outside looking in and finally risks getting hurt if it means fighting for what he feels in his heart. His relationship with Dr. Jeffrey Squires is the centerpiece of the film, and it's notable for not being a makeshift father-son one, but between peers who happen to be decades apart in age. This is Ben Kingsley's most accomplished performance since 2003's "House of Sand and Fog," and he is wonderful at making Squires an almost childlike presence forced into coming to terms with some very mature decisions.

As Stephanie, Olivia Thirlby continues to impress with another impeccably developed teen role that is widely diverse from the ones she played in 2007's "Juno" and 2008's "Snow Angels." That is the mark of a real actor with range, and what could have been a somewhat off-putting character here is too well-drawn by Thirlby to not be likable enough to understand why Luke thinks she's worth his attention. Famke Janssen (2006's "X-Men: The Last Stand") has a more difficult part to take on, since Kristin has less screen time and, thus, less time to shade her character. Still, Janssen does a nice job in making Kristin feel real, even if she is just a little bit shrewish. The scenes between Kristin and Squires have a detached, uneasy feel, and that's as it should be, since their marriage is falling apart. Finally, in her first film project sans Ashley, Mary-Kate Olsen (2004's "New York Minute") is vibrant and loose as Union, a hippie chick whom Squires shares a fleeting connection with. In some ways, she is the catalyst for Squires' decision to make a change in the unhappy lifestyle he has been leading.

In addition to being a smart coming-of-age story, "The Wackness" wins extra points for so vividly bringing to life the summer of 1994. That doesn't seem like very long ago for those old enough to remember it, but a lot has changed since then in terms of technology, music and fashion, and the film exactingly captures this without needing to call attention to it. The soundtrack, a mixture of rap, hip-hop, R&B and rock from the era, is compiled with loving attention. It's easy to see why "The Wackness" was such a crowd-pleaser at Sundance. The story itself isn't a complex one, but the characters are, and the journey they endeavor upon from the month of June to the dog days of August is one that is emotionally satisfying, easily relatable and well worth taking.