Kick-Ass is based on the comic book of the same name by Mark Millar and John Romita, Jr. The plot concerns a teenage boy, Dave Lizewski, who decides to become a real-life superhero after being inspired by the heroes of comic books. He soon encounters a mysterious vigilante called Big Daddy and his daughter Hit Girl, who are working to bring down the local drug baron Frank D'Amico. He also meets another vigilante, Red Mist, who has been inspired by Kick-Ass.