Sun Valley Film Festival founder Teddy Grennan was driving through central Virginia near his home in Charlottesville when he stumbled upon a feature news segment on NPR in which a rancher was discussing the use of pesticides and GMOs in cattle.

“The reporter from NPR was trying to get this rancher to talk about how pesticides and GMOs were bad for cows,” says Grennan, “and the rancher let the [reporter] finish and then says, ‘let me tell you something. The inside of a cow is one of the most toxic environments in the world. You put anything in the world in there and it’s going to digest it.’ And I thought, what if you stuff a person in it?”

That one thought — dark and twisted as it may be — formed the basis of what would become Grennan’s directorial debut, “Swing Low,” an indie slasher movie that he wrote with the singular artistic purpose of turning the horror genre on its head. The film, starring “Succession” actress Annabelle Dexter-Jones as a feisty and resourceful nature photographer who unearths a culture of macabre violence in Virginia’s Watchatoomy Valley, premiered at GenreBlast Film Festival in Winchester, Va., where it won best picture. “Swing Low” has since screened at numerous other fests such as Horrible Imaginings, Nola Horror Film Festival and Austin Film Festival, where “the crowd went wild for it,” says Grennan.

“If you read about the history of the cruelty of humanity and what these kings of pain, these Europeans, did to each other during Medieval times—they took great pride in naming their methods of torture,” notes Grennan. “The cruelest were the Portuguese. They would tie people to a rock and let the tide roll in. There’s a whole history to these lords of pain — we actually almost named [the film] ‘Lord of Pain.’ So I tied this whole history into [the storyline about] the cows. I married these two things together. And people say it’s really interesting.”

But with its twinkly golden-hour cinematography and lush woodsy wide-shots (courtesy of cinematographer Christopher Walters) “Swing Low” is a striking juxtaposition between flashing hints of barbaric torture and quiet, slow moments of soft, sunlit beauty. In terns of visual aesthetics, if “One Golden Pond” met “Chainsaw Massacre” that would be “Swing Low.”

The project is also in stark contrast to the visual of Grennan himself. Born in Falmouth, Mass. and raised in Stowe, VT., the New England prep school delinquent was kicked out of both the Fessenden School and Portsmouth Abbey School as a teen.

“I was asked politely to leave,” quips Grennan, who went on to graduate from University of Vermont with a degree in English. Today, Grennan is rarely caught dead in anything that doesn’t scream “Ralph Lauren nautical chic.” Attend the annual Sun Valley film fest, to be next held March 18-22, and you can be sure to find Grennan decked out in an ascot, more Captain Merrill Stubing than Wes Craven.

But there’s also a side of Grennan that was particular drawn to this idea of exploring violence in the world — not for violence sake, but “to shake up the horror genre.”

“In most of these genre films, the girl barely comes out alive,” he says. “Or she never picks up the gun. In ‘Swing Low’ you have this very capable protagonist who does get the motherf—ing gun and let’s the guys have it.”

Grennan first pitched the idea around 10 years ago to television and film producer Marsha Oglesby (“Sky Captain and the World of Tomorrow,” “Righteous Kill”) while they were out partying at a Los Angeles bar.

“I’d been working on an animated script for Nickelodeon called ‘Holy Cow’ about this young bull who realizes his future will end up on somebody’s backyard barbecue grill and he and this caterpillar go to India, and [Marsha’s] like, you got a thing for cattle don’t you?” Grennan recalls. “And she said, if you can tell this story exactly the way you told it to me then I can raise the money.”

Funding fell through twice, Gersh swept in and helped secure financing for a third time and, ultimately, “Swing Low,” which also stars Bruce Dern, was made for under $1 million dollars.

“We shot it in shot it in Charlottesville, which provides an aggressive and reasonable rebate on film projects made there,” says Grennen, who is currently gearing up for Variety’s winter screening series taking place in Sun Valley Dec. 27-28.

“I wrote it like a play,” he continues. “Dern’s house [in the film] is my house, the barn is [wife Emily Granville’s] barn. I just used all the toys and assets we have to keep costs down. I sold my Jaguars to finish this film. It was all home grown. That saying, it takes a village? In our case, it takes a valley.”

“Swing Low” most recently screened Oct. 30 at Austin’s Galaxy Highland Theater.