Werner Herzog’s insane determination to haul a 308-tonne steamship over an Amazonian mountain for Fitzcarraldo is the stuff of legend. She laughs at the (admittedly flippant) comparison, but it sounds as if Helen Haig-Brown and her partners on Edge of the Knife were hardly less guilty of tempting failure with grand ambition.

“I remember initially just thinking, ‘Jesus, are we for real?’ ” she tells the Straight about the 19th-century period piece, shot on Haida Gwaii and told entirely in a language remembered by fewer than 25 people. Certainly, nobody in the film’s cast of relatively youthful nonactors was fluent in the two dialects of Haida. All the same, Haig-Brown continues, “We knew that’s what was right and what had to be done. But it was certainly scary as a filmmaker.”

Directed with Gwaai Edenshaw, Edge of the Knife (Sgaawaay K’uuna) tells the story of Adiits’ii (Tyler York), who retreats into the forest after a tragic misadventure with a young boy. Beset by grief and accosted by spirits, he gradually transforms into the Wildman, or Gaagiixiit, deriving from a Haida tale that surfaced during community screenwriting workshops stretching back to the project’s origins in 2012.

York’s commitment to the role is hair-raising. In part, Haig-Brown reveals, it’s due to the training he did with stuntman Clint Carleton, who worked as an Orc movement coach on the Lord of the Rings trilogy. But there’s more to the performance than just intense physicality.

“We were initially very worried about it, and we had different ideas about how to get him into preparation, how to have spiritual support,” Haig-Brown says. “Because, remember, transforming into Gaagiixiit—this is a very real thing that happens.”

The filmmaker hesitates to say more, adding that it might be more appropriate to let her Haida codirector talk about it. But, she says, “I know it was a very emotional journey for everyone because no one got to see Tyler. We isolated him. When he gets captured and brought into the village—there were real tears shed at that time. It’s the underlying story: how we can lose people, either through madness or emotional strife or drug addiction; how people can run from things, and how it is part of our responsibility as a community to never leave somebody behind, to bring them back. We all relate to that feeling. We’ve all had somebody in our life, you know?”