Big Apple photographer Nev Schulman, his brother Ariel and buddy Henry are hip young media gunslingers working out of a achingly fashionable downtown Manhattan studio.
Cool and savvy, they're nonetheless intrigued when Nev receives a painting based on one of his photos by an eight-year-old girl from rural Michigan.
She's Abby. She's got 83 Facebook friends, a pet snake called Zoe and is making a name for herself locally as an artist. Abby's mom is Angela, who proudly tells Nev that one of her daughter's paintings sold for more than $7000.
However, as the emails, wall postings and text messages fly, the family member Nev is most attracted to is Megan. She's Abby's half-sister, whose Facebook profile shows a clear-skinned beauty who writes songs, loves horses, studies ballet but still knows how to party.
Megan and Nev's cyber friendship blossoms into heated romance. "How am I going to keep my hands off you," she gushes in fruity terms you don't normally expect from a pen-pal.
To add extra frisson to the unfolding relationship, Nev's auteur colleagues Ariel and Henry have been filming, fly-on-the-wall-style, every exchange - from the arrival of Abby's painting parcels to Megan's saucy texts and suggestive messages.
OK. it's not very chivalrous...but documentary dynamite. Particularly, when cracks begin to appear in Megan's story. It turns out that "self-penned" MP3s she's sent to Nev turned out to have been ripped from YouTube.
Nev ponders whether he's been done up like a kipper. Ariel and Henry keep filming. There's only one thing to do - head off on a road trip to Michigan to meet the real, Angela, Abby and Megan.
Although marketed as some sort of cyber thriller, this is far closer in tone to the sublime doc Capturing The Friedmans by Andrew Jarecki, who just happens to be one of the producers.
What happens next is not shocking but profoundly sad. Co-directors Henry and Ariel together with Nev discover someone deeply damaged for whom the internet - particularly the social networking community - provides the anonymity to live out a fantasy life.
But the white heat of technology - from satnav to smartphone, from YouTube to Facebook - has the potential to burn...and this cautionary tale - which itself has been accused of being a hoax - demonstrates the downside of uploading.
Tim Evans is no longer on Facebook.