Everyone knowns Canadians are lousy at self-mythologizing. Our disinclination to toot our own horns is one reason we’re also lousy at producing movie stars. Scratch that—we’re great at producing them (everyone from Mary Pickford to Mike Myers); we just suck at keeping them around. The Canadian club of starry-eyed wannabes who pack their bags for L.A. every pilot season is much larger than your average Soulpepper audience. The talent that does stick around tends toward the defiantly patriotic.

Paul Gross is that most mythic of creatures, the homegrown star who made his name on the home front and never strayed (unless you count 1993’s Aspen Extreme, which he would probably rather you didn’t). In his hunky, bankable way, he embodies the possibility that Canadian cinema might have something significant to offer. Something like a World War I epic written by, directed by and starring Gross. Passchendaele will open the festival this month, and while he says he was too busy to pay attention to which film was being chosen (when we spoke, he was deep into the editing process), the premiere is a make-or-break moment for the 49-year-old filmmaker. At $21 million, Passchendaele is the most expensive movie ever fully funded and made in Canada. The stakes are high—Waterworld high.

This judgment day has been years in the making. Gross’s résumé reads like a crash course in CanCon: following an early play about the Alberta badlands, he was promptly dubbed our Sam Shepard. More recently, he has played a fictional Canadian PM in H2O, and a real one—John Diefenbaker—in The Tommy Douglas Story. In between, he starred in Slings and Arrows (the beloved series about a Stratfordesque theatre festival), and of course, there was Due South. Gross’s role as a smouldering Mountie in the ’90s comedy series remains his calling card despite regular attempts to pene­trate Canada’s cabal of serious filmmakers. Not surprisingly, 2002’s Men With Brooms, a movie about curling that Gross wrote, directed and starred in, failed to catapult its leader to auteur status. (Variety called it “ultra-corny.” It was.)

This time around, his subject is a lot weightier and has personal resonance for Gross. His grandfather Michael Dunne fought in the Passchendaele bloodbath, during which 16,000 Canadian soldiers died for a nine-kilometre advance. On a fishing trip, Dunne told his grandson about bayonetting a German soldier. “Our history isn’t what we imagine it is,” Gross says, referring to Canada’s peace­keeping reputation. “We’ve also been warriors.”

The filming of Passchendaele—which required platoons of extras and 15,000 barrels of water a day to recreate the muddy, bloody battleground—lasted 64 days, which was nothing compared to the uphill battle Gross faced collecting the money to make it. After securing $9 million from the Alberta government and Telefilm Canada, he took his golden boy rep cross-country to pry the rest of his budget out of private investors. Still, making an American-style blockbuster in Canada can be like trying to use your Cana­dian Tire money at Disneyland, and few, if any, domestic film­makers could pull off a similar feat. Such is Gross’s seductiveness—a confident, folksy charisma that makes the fervid fanaticism of Due South devotees entirely understandable.