Kick-Ass is a 2010 superhero action thriller based on the comic book of the same name by Mark Millar and John Romita, Jr. The film was directed by Matthew Vaughn, who co-produced the film with actor Brad Pitt, and co-wrote the screenplay with Jane Goldman. The film's general release was on 26 March 2010 in the United Kingdom and on 16 April 2010 in the United States.
 
The film tells the story of an ordinary teenager, Dave, who sets out to become a real-life superhero calling himself Kick-Ass. Dave gets caught up in a bigger fight when he meets Big Daddy, a former cop who, in his quest to bring down the evil drug lord Frank D'Amico, has trained his 10-year-old daughter to be the ruthless vigilante Hit-Girl.
 
Kick-Ass has generated some controversy for its profanity and violence, particularly for the character Hit-Girl. The film received mostly positive reviews.
 
Dave Lizewski (Aaron Johnson) is a normal teenager who wonders why nobody has ever decided to become a superhero like the ones in the comic books, so he decides to become a real-life superhero, despite having no superpowers  or training. During his first attempt to fight crime, Dave is beaten, stabbed, and hit by a car. Some of Dave's nerve endings are damaged as a result, giving him an enhanced capacity to endure pain, and metal plates are placed in his skeleton to support his bones. After a painful recovery, Dave returns to school only to find out that his longtime crush, Katie Deauxma (Lyndsy Fonseca), is interested in him, but only because she thinks he is gay. Dave goes along with this in an effort to spend time with her.
 
Undeterred by his setback, Dave continues to patrol the streets. One night, he comes upon a gang fight and defends the single victim from his attackers. A bystander records the event, as well as Dave calling himself "Kick-Ass". The video becomes a YouTube phenomenon, and Dave sets up a MySpace account so people can contact Kick-Ass.
 
Katie tells Dave that she is being harassed by a drug dealer, so he convinces her to ask Kick-Ass for help. Kick-Ass tracks down the drug dealer to deliver a warning, he threatens the drug dealer, tasers him, but is subdued by the dealer's henchmen, who appear intent on killing him. He is rescued by child costumed vigilante Hit-Girl (Chloë Grace Moretz), who kills his attackers and then leaves with her father, Big Daddy (Nicolas Cage). They later easily track down Kick-Ass, and inform him that they can work together, and they will keep in contact.
 
Big Daddy is revealed to be Damon Macready, a former cop who was framed by local crime syndicate leader Frank D'Amico (Mark Strong) because D'Amico saw him as a threat to his organization. While Damon was in prison, his wife overdosed on sleeping pills and died shortly after giving birth to their daughter, Mindy. After his release, Damon trained Mindy to fight crime as Hit-Girl and he became Big Daddy.
 
Believing Kick-Ass to be responsible for damage done to his organization, D'Amico orders his men to find and eliminate him. After D'Amico kills an imposter dressed as Kick-Ass, his nerdy son, Chris (Christopher Mintz-Plasse), suggests a different approach. Chris will pose as a superhero named Red Mist to trick Kick-Ass into trusting him, and lead him into a trap. Red Mist meets Kick-Ass, bringing him to D'Amico's warehouse to "ambush" his men. Instead, they find the building on fire with everyone inside dead. Red Mist retrieves surveillance footage which shows that Big Daddy is responsible.
 
Realizing the seriousness of his situation, Dave wants to quit being Kick-Ass. He tells Katie the truth, and she understands and eventually becomes his girlfriend. Some time later, Dave finds urgent messages from Red Mist, requesting they meet, and to find Hit-Girl and Big Daddy. Kick-Ass leads Red Mist to one of the Macready's safe houses, with D'Amico's men following. Red Mist shoots Hit-Girl, knocking her out of a window. Big Daddy and Kick-Ass are captured and taken to a warehouse to be beat and tortured in a live Internet broadcast. Kick-Ass and Big Daddy are severely beaten, and Big Daddy is set on fire, when Hit-Girl, who survived by wearing a bulletproof vest, arrives and kills the gangsters, and destroys the camera trying to film the unmasking of Kick-Ass and Big Daddy. However, Big Daddy is badly burned and dies from his injuries. Kick-Ass tries to convince Hit-Girl to quit, but she plans to finish what her father had started, and Kick-Ass reluctantly agrees to help.
 
Posing as a schoolgirl, Mindy enters D'Amico's headquarters and kills most of the henchmen in the penthouse, but runs out of ammunition. Just as one of D'Amico's thugs is about to shoot her with a SMAW rocket launcher stolen from Macready's safe house, Kick-Ass, armed with a jet pack fitted with gatling guns that Big Daddy had purchased prior to his death, kills the remaining men. He then takes on Red Mist and they knock each other out. Hit-Girl fights D'Amico, but she is eventually overpowered by him. As D'Amico is about to finish off Hit-Girl, a revived Kick-Ass fires the bazooka, blasting D'Amico out of the window where he explodes in mid-air. Red Mist comes around to find Kick-Ass and Hit-Girl leaving on the jet pack.
 
Hit-Girl and Kick-Ass retire from crime fighting to live a more normal life. Mindy, now in the custody of Damon's ex-partner Sergeant Marcus Williams, enrolls at Dave's school. Dave explains a new wave of superheroes have been inspired by his endeavor. In the final shot, Red Mist, having taken over his father's business, dons a new mask and declares war on the new hero population quoting the Joker, "as a great man once said, 'Wait'll they get a load of me'".