"My friend sent me this link about a weird sport in Los Angeles where young men are flown, often monthly, to be tickled and they're paid really well to do it," he explains.
"I just thought, 'This is so great. Kiwis have been flown over to Los Angeles to be tickled, in a sport, they get paid for it,' and it's all like ... 'what?'"
But that's only the start of the story. Farrier started blogging about it, his co-director Dylan Reeve joined him, and they soon realised they had something bigger than a three-minute news segment could cover.
Reeve: "There was suddenly a lot of negative reaction ... people saying, 'This is wrong, there's no story here.' As soon as we saw that, we knew there was a story. Once we learned more about what was going on, and the story was so complex, we figured there was some meat there to make a cool documentary and expose what we'd discovered."
Farrier says it "only gets weirder from there". As the pair began pursuing the creator of the sport, a man the Herald reported in 2014 to be David D'Amato, and his company Jane O'Brien Media, legal threats started piling up in their inbox.
Or, as Variety put it: "The documentary's first big reveal arrives a little more than halfway through, and more twists will follow, with a mysterious zip file and a treasure trove of online documents tracking the digital-age saga to Long Island high schools, a Wall Street law firm and federal crimes."
Other positive reviews came from Screen Daily ("Unexpectedly compelling, funny and deeply sad."), and THR ("Farrier's dry Kiwi humour infuses proceedings with a relaxed energy").
Farrier says the film - his second attempt at a documentary after his search for the Mongolian Death Worm in 2009 proved fruitless - was made on a shoestring, one that included a $25,000 Kickstarter fund.
He and Reeve didn't believe they had something worthy of a Sundance premiere on their hands.
"We thought it would be a neat little thing on Vimeo," says Farrier. "It was low key. We were so appreciative of our friends who came on board and did stuff for free and loaned us cameras, because they saw there was a cool little story there."
Help also came from pro bono lawyers to help clear the legal threats hanging over the film. Asked about those threats now, Farrier only says: "We're in a position where we feel like they're under control."
It's all about the story, and Farrier, who recently quit TV3 after a 10-year career there, says Tickled is the find of his journalistic career.
"I'm not kidding myself, I think it will be incredibly difficult to make something like this again. (Reeve and I) both have ideas floating around in our heads (for another film) but we'll get through Sundance and go from there. It's pretty impossible to make documentaries for a living.
"We'd both love to make another film but the right things have to fall into place."
In the meantime, Farrier and Reeve are hoping their positive Sundance reviews lead to someone buying their film and getting it into cinemas - something a New Zealand release depends on.
"My mum hasn't seen it," says Farrier. "That's ridiculous."
- nzherald.co.nz
