Charming and clever, Dan Dunne (Ryan Gosling) is a great teacher. Lecturing about history in an inner-city junior high school, Dunne connects with his disadvantaged students, teaching the kids about how opposing forces shape current and past events—and when he's not teaching, he's coaching the school's girls' basketball team. And all this makes it pretty awkward when one of his smartest and most troubled students, Drey (Shareeka Epps) catches Dunne smoking crack in the locker room.

Not exactly a light-hearted premise, that, and in the excellent Half Nelson, things only get trickier. A small, hard-hitting character study, it's hard to find fault with the film—on nearly every level, director Ryan Fleck and screenwriter Anna Boden (who co-wrote the film with Fleck) keep things sharp, real, and truthful.

At the heart of the film is the strange but earnest friendship between Drey and Dunne. Drey plays basketball and is in Dunne's class; with a mom who's rarely home, a brother who's incarcerated, and a neighborhood dealer (Anthony Mackie) who seems like he's the only person watching out for her, Drey's bond with Dunne is one of both need and wary hope. Dunne, meanwhile, is in an equally tough spot—having given up on going sober, he lives alone, drinks, neglects his cat, and freely admits he's an asshole. Ducking out from an awkward school dance to snort coke behind the gym, the miserable Dunne's a profoundly fucked-up individual, and he knows it—making things even weirder as his tentative, awkward friendship with Drey develops.

But that relationship is at the heart of Half Nelson, and it's utterly believable—Gosling's excellent, almost unrecognizable from his shameful The Notebook days, while the preternaturally talented Epps creates a character both subtle and heartfelt. The greatness of Half Nelson isn't in its thorny concept, nor in its understated execution—it's in these two characters. By the time the end credits roll, it's evident that Half Nelson is truly excellent filmmaking—as intellectually complex and difficult as it is emotionally engaging.