Ideally, here’s what you should know about Catfish before seeing it: nothing. Nada. Just buy a ticket, sit down, and let the story unfold. But because you’re probably a little curious, here’s a taste of the documentary’s plot.In 2007, Nev Schulman, a 24-year-old New Yorker, receives a painting in the mail. It’s an oil rendering of one of his photographs The New York Sun had published. The sender: Abby Pierce, an 8-year-old girl from rural Michigan.Nev begins a correspondence with Abby, her mother Angela, and Abby’s 19-year-old sister Megan. At the same time, his brother Ariel and friend Henry begin documenting the experience. When Nev enters into an online relationship with Megan, the trio decides to arrange a trip to Michigan to meet the family.But that’s all you should know — because it’s only the first half of the movie. And the second half is completely unexpected.Catfish opens September 17. If you insist on finding out even more, watch the trailer online at iamrogue.com/catfish.