"The first thing," says Jean-Marc Vallée, director of the triumphant Quebecois film C.R.A.Z.Y., "is to be humble and trust the script. A humble director... you don't see him, you don't hear him. The story is the star. You don't need to see how clever the director can be." At this, a bashful smile spreads across his face. "Of course," he concludes sheepishly, " I do like to punctuate things sometimes."

Does he ever: C.R.A.Z.Y., which spans three turbulent decades in the life of a middle-class Montreal family, is an everything-and-the-kitchen-sink drama (derived in large part from the director's own formative experiences, and those of his co-scenarist François Boulay) shot with a potent charge of magic realism. Sensitive Zac (played as a teenager and young adult by the remarkable Marc-André Grondin), the fourth of five sons, struggles with sexual confusion and the strain it places on his relationship with his clenched father, Gervais (Michel Côté). There's something about this subject matter that often provokes allergic reactions in audiences -- perhaps it's the deluge of coming-of-age-and-out films we see during festival season -- but C.R.A.Z.Y. never feels weighted down by its lead character's emotional baggage.

In fact, the film is so sure-footed that it rarely seems to touch the ground. Vallée acknowledges his debts to such prominent Quebecois filmmakers as Denys Arcand, but says his biggest stylistic influences hail from Hollywood. "I love Martin Scorsese," he says. "I love him. But then, Scorsese is sometimes like this" -- he gestures quickly with his hands, making loud popping noises, as if playing both Travis Bickle and his victims in a one-man revival of Taxi Driver.

It's not an exaggeration to say that parts of C.R.A.Z.Y. have the moodiness of vintage Scorsese; the opening scenes, set at the beginning of the 1960s, have an inky, enveloping depth that suggests the addled wonderment of childhood. Young Zac is given a rough ride by his combative brothers and spoiled by his father. He's closest with his mother, Laurianne (Danielle Proulx), who suspects Zac of harbouring spiritual abilities. When the scene shifts to the 1970s, Zac has transformed from a shy kid to a gorgeous, Bowie-aping teenager: still an outsider, but now cocksure and self-possessed. Laurianne still dotes on him, but Zac, for all his burgeoning confidence, just can't please Gervais, who is terrified at the prospect that his son might be gay. His intolerance is truly felt, but also hypocritical, given his own distinctly un-macho passion for old Patsy Cline records.

If the story reads as turgid, it rarely plays that way. Vallée's achievement is to ground his potentially sudsy domestic opera in a raw and realistic context. "I told everybody: less is more," he says. "This is the law. This is the first, second, third and fourth commitment that we must honour. We have on our hands a dramatic film that could become melodramatic. Melodrama is too big... I'm never touched by melodrama. This is why I often filmed the actors from the back, or in soft focus. I didn't always want to see their faces and emotions."

There are, however, moments where Vallée simply allows his lead actor's visage to speak for itself. One crucial passage finds Zac alone in his room, lip-synching along to David Bowie's "Space Oddity" in full Ziggy regalia -- a bedroom devotional confirming that his stifled Catholicism has been supplanted by rock 'n' roll mania. The scene concludes with Zac brought roughly down to Earth by a shove from his disapproving brother. Vallée says that he felt so strongly about the symbolic heft of this gesture -- metaphorically, it represents the refusal of Zac's family to accept his hard-fought otherness -- that he insisted on doing the shoving himself from off-camera. (He also admits that he let Grondin shove him back afterwards, in order to soothe the actor's bruised ego.)

The anecdote serves to illuminate why C.R.A.Z.Y. took a decade to make: its director simply refused to make compromises. "It took 10 years to write the script," Vallée reports. "It became almost like a meditation. Four years part-time, one year full-time... and then I asked my collaborator François Boulay -- it's based on his life by the way -- to let me write the film that I wanted to write. I said, 'Let me tell your story, François. We're going to make a good film.' We're like circus people... we train and we train, to give a good show."