'Batkid Begins' in Theaters Friday: See the Trailer

— -- A superhero, super-uplifting film that does not involve an A-list movie star playing the lead is swooping into movie theaters this Friday.

The documentary “Batkid Begins” takes an inside look at the 2013 Make-A-Wish event that turned a young boy into Batman and San Francisco into Gotham, and in the process captured the nation’s attention and hearts.

The star of the documentary is, of course Miles Scott, the then-5-year-old California boy who was battling leukemia and had a wish to turn into Batman.

Batkid's Family Paying It Forward With Superhero Fund

The Make-A-Wish Foundation’s Greater Bay Chapter and the city of San Francisco made his dream come true.

On one day in November 2013, The San Francisco Chronicle's entire front page was dedicated to Miles; he had his own Batmobile and was led on a city-wide adventure that included rescuing a damsel in distress, foiling the Riddler's bank robbery and saving San Francisco Giants’ mascot Lou Seal from the Penguin.

More than 20,000 people turned out in San Francisco to cheer on Miles that day and now thousands more will have the chance to see how the day came to be, thanks to filmmaker Dana Nachman, the documentary's director.

"I saw this happen and was really interested to know what happened behind the scenes," Nachman told ABC News of the event, which inspired more than 600,000 tweets with the #SFBatkid or #Batkid hashtags, the Make-A-Wish Foundation reported at the time.

"What would make something go so viral?," Nachman said she asked herself. "People saw it in 140 words through tweets but what were the mechanics behind it to make that happen?"

Nachman, a 43-year-old mother of three who lives in San Francisco, says about half of the documentary's footage is new and the rest comes from the Make-A-Wish Greater Bay Area, local news coverage and footage from the Scott family themselves.

The documentary's focus is largely on people like Make-A-Wish Greater Bay Area Executive Director Patricia Wilson, the woman who spearheaded the entire day, and volunteers like Eric Johnston, the man who played the grown-up Batman next to Miles.

"I didn't expect this but the story is not about Miles but about these amazing people who came together to make this amazing day for a child," Nachman told ABC News. "It was 10 to 20 people who put their all in for this day. They didn’t know 25,000 people were going to show up. They were just doing it for this boy."

Nachman recalled the example of Johnston, an inventor-acrobat-stunt double known as EJ, who would not settle when some suggested a message from the city's police chief be relayed to Miles via iPhone.

"EJ said it would just be like an adult on an iPhone and wouldn’t it be cooler if I projected it on something that I invented myself and he did," Nachman said, describing a moment in the documentary. "He invented a way to put it on a small computer projector on his wrist instead."

"It was lots of little things like that, plumping it up to make it just the ultimate day, not only for a 5-year-old but everyone who watched it in person and online," she said.

The documentary, which premiered at this year’s Sundance Film Festival, took Nachman nearly one year to complete. She is donating all of her proceeds from the film to the Batkid Fund, a charity started after Miles's Make-A-Wish day.

“Batkid Begins” opens in select theaters in New York City, San Francisco and Los Angeles on Friday. The documentary is expected to be released in 25 more cities on July 10, and may expand even further after that.

"I think people know the story, the Twitter version of the story, and once they see what really happened behind the scenes they’re going to be even that much more awe-inspired," Nachman said. "It’s a beautiful experience that so many volunteers had."

The story inspired by Miles, who is now nearly 7 and in remission, will not stop with the documentary. Warner Bros. has optioned the story, with Oscar winner Julia Roberts signing on as both producer and star.

Nachman has joined the theatrical release as an executive producer.

"This story is about the end of a horrible chapter in his life," Nachman said of Miles. "His wish marked the end of that chapter and a new beginning."

Watch the "Batkid Begins" trailer here: