"My leaving for the U.S. is very painful," he continued, surrounded by some of the other boys. "It is not simple. You can see and judge that you will miss a company like this. It is like my family now. … I love them so much."
The filmmakers follow Dau and a group of the boys as they board a plane for the first time and embark on their long flight to America. Some giggle with excitement, but others look confused as they struggle with the overhead luggage bins. When they're served airline meals, one boy unwraps a pad of butter and eats it whole, not realizing what it is, and says, "It tastes like soap."
Others seem bewildered as the airplane captain's voice is heard coming from a mysterious series of tiny holes in the panel above their plane seats. "The voice … where does it come from?" one boy asks.
For the boys, who learned to speak English while living in the refugee camps, everything is new. Even the simplest things like riding an escalator posed a new set of challenges -- and at least one of them has a bit of trouble as he navigates the first couple of steps.
As the "lost boys" arrive in their new homes, there is much to learn about life in America, and the modern conveniences some of us take for granted.
"This is a shower," explains the aid worker who was showing them around their new apartment. "We do not throw things out the window here," he tells them as they crowd into the kitchen. They learn to turn on the lights. "The first thing you have to learn is switch to turn the light on and off," he tells them.
The boys also have an adventure at a grocery store where they seem like visitors from another planet. One thing is clear: They have never seen so much food, and in so many colors.
"Is this food?" one boy asks as he points to a doughnut with colored sprinkles on top. "Hoagie buns?" another says looking at the endless choices of bread in various forms.
The movie became the passion project of filmmaker Christopher Quinn shortly after he read about the refugees, and decided to act.
"I was reading about Sudan, and the devastation that had taken place there," he says. "And I stumbled onto an article about the 'lost boys,' and I knew at that point I was going to make a documentary about them … the story is so compelling."
As Quinn continued to follow the new lives of Dau, Bior, and Pach, his film became increasingly expensive. Months turned to years, and when it came time to edit the film, Quinn began to run out of funds. He turned to his childhood friend, actor Dermot Mulroney, who was well-connected in Hollywood.
Mulroney recalls that Quinn came to him and says, "We don't have another cent to complete this film. This is the end of it, unless we figure something out."
Mulroney was eager to help and put Quinn in touch with his friend, Pitt, who took an immediate interest in helping the struggling filmmaker finish editing what, he believed, was an important film.
At the film's premiere, Pitt told ABC News that "I was fortunate to come in at kind of the last minute, and get to throw up the last shot. These guys have been working on it for several years and friends of mine, Dermot Mulroney and Catherine Keener, are very tight with the director. They showed me some rough footage, and I was really moved by the story and jumped in the game. I personally can't imagine being thrown out of my home, being separated from my family."