In “Half Nelson,” a 26-year-old Ryan Gosling plays Dan Dunne, a middle school teacher who clearly has a gift for connecting with his students but whose life is falling apart outside the classroom. After what was an extremely tough breakup for Dunne, he fell into drug use and spends most of his free time either scoring increasingly serious substances, languishing in his bare-bones Brooklyn apartment, or slipping into a drug-induced stupor. After he’s discovered in the midst of one such stupor by his own student, Drey (Shareeka Epps), he and the youngster form a bond that has the potential to help bring Dunne out of his addiction.

Throughout “Half Nelson,” Gosling uses his effortless charisma in a more subtle way than we’re used to, helping tell a truly affecting story about substance addiction and the connections human beings can form across social and cultural boundaries. When Dunne is interacting with his students, or on a date, he’s coolly beguiling. When he’s in the depths of his loneliness, he’s palpably tortured. All of it is believable.

But Gosling isn’t the only reason to see “Half Nelson.” Shareeka Epps is outstanding as Drey, especially considering this was her first film role and she was just 16 at the time of filming. Since “Half Nelson” we haven’t seen much of Epps — though she has appeared in odd roles here and there. But that’s truly a shame, because her performance here is so elegantly composed that it’s genuinely unbelievable that this was her first major role in film or TV.

With all this in mind, despite the fact that you don’t hear “Half Nelson” mentioned much, it’s nice to see the film ranked as Gosling’s second-best movie of all time on Rotten Tomatoes.