Here’s a wild plot for a film: Three identical triplets are separated at birth, adopted to different sets of parents and raised without awareness of one another. Then via pure chance they are brought together 19 years later. The twist is it’s a movie — but a documentary, not a narrative feature. It’s Tim Wardle’s Three Identical Strangers, which is bowing in the U.S. Documentary section of the Sundance Film Festival.

The 1980 reunion of Bobby Shafran, Eddy Galland and David Kellman made them media magnets —  they were tabloid stars, and together owned a successful Manhattan restaurant. But it also set in motion a chain of events that unearthed an extraordinary and disturbing secret.

CNN Films, RAW and Becky Read are producers of the pic, which bows Friday at 12:30 PM at the Ray. Submarine is selling rights in Park City, and it will air later this year on CNN.

Check out the exclusive clip above that reveals the way all of it came to be, when a chance encounter helped one of their friends put it all together.