Filmmaker Dana Nachman has raised nearly $50,000 -- about half of what's she's seeking -- to finish the official Batkid documentary, "Batkid Begins."

The film follows 5-year-old Miles Scott, a leukemia survivor who asked the Make-A-Wish Foundation last November to be transformed into Batkid for a day in San Francisco. The official trailer for "Batkid Begins" was launched Monday:



The event drew 25,000 people to the streets to cheer Batkid on and was seen by nearly 2 billion people across 117 countries. Ben Affleck and Christian Bale weighed in, calling Scott "the best Batman ever."

2014 Variety Media, LLC, a subsidiary of Penske Business Media; Distributed by Tribune Content Agency, LLC