Dave Lezesky (Aaron Johnson) is like all ordinary boys, dreaming of becoming a superhero one day, but he has brought his dream into reality. After buying a cheap green jumpsuit online, Dave began to fight crime alone. Although Dave was seriously injured in the first action, Dave is not a person who gives up easily. After recovering from his injury, Dave was discovered and photographed by enthusiastic people when he was trying to stop a fight. After that, the story of the superhero "Kick-Ass" spread throughout the city. Dave, who has become a legendary superhero, meets superhero father and daughter Big Daddy (Nicolas Cage) and Hit-Girl (Chloe Moretz) during an operation. After that, Dave is used by the hero Red Tornado (Christopher Mintz-Plasse), disguised as the son of Frank Amick (Mark Strong), the boss of the drug cartel, and Big Daddy and himself are imprisoned. In times of crisis, Hit-Girl appears in time to rescue Dave, but Big Daddy unfortunately dies. Hit-Girl decides to fulfill her father's will and completely eliminate the drug cartel... This film is adapted from the famous comic of the same name by Mark Millar.