In Jonathan Levine's sharp little movie, the baby-faced Josh Peck stars as Luke Shapiro, a low-level pot dealer whose life is fraying around him. Having just graduated from high school with near-anonymity intact, Luke spends his days peddling weed to regular clients, and his nights listening to his parents fight. His only outlet—outside of the barrage of hiphop he listens to incessantly—is a weekly visit to a psychiatrist, Dr. Squires (Ben Kingsley), a crumbling quack who, when he's not dispensing dubious advice, is abusing Luke's product.

This odd friendship between doctor and patient—forged via pot, cemented thanks to loneliness, and eventually strained by Luke's crush on the Dr. Squires's fetching and popular stepdaughter Stephanie (the crushworthy Olivia Thirlby)—spins at the center of The Wackness. And for the most part, it feels authentic. Whether confined to Dr. Squires's dim office or following Luke and Dr. Squires on deliveries, the movie is at its strongest when the two leads occupy the same frame. Kingsley definitely has the showier role (and man, does he run with it), but it's the former Nickelodeon poster boy who truly shines. His eyes at perpetual half-mast, his delivery lazy and mushmouthed, Peck brings an honesty to Luke that simply outclasses everything else in the film.

Set in mid-'90s Manhattan, The Wackness falters occasionally (the subplot of Dr. Squires's failing marriage is especially malnourished), and Levine's direction sometimes risks being too flashy for the material. But for every brief stumble there's a moment—including one of the more realistic loss-of-virginity scenes you'll ever see—that rings absolutely true. Given the number of movies that are entirely plastic these days, that alone makes The Wackness worth seeing.