Kick-Ass Storyline

Dave Lizewski (Aaron Johnson), a typical teenage boy, wonders why no one has ever decided to become a real-life superhero like the heroes in the comic books. His friends at a comic book store told him that if anyone did become a superhero, they would get their ass kicked. Lizewski fails at his first attempt to fight crime, he is beaten, stabbed, and hit by a car. He convinces paramedics to say nothing of his costume and pretends he was brought in naked. In hospital for several weeks he is left with metal holding his bones together which he says looks like Wolverine. He has also suffered nerve damage which gives him an above average ability to take a beating. When he returns to school his longtime crush, Katie Deauxma, seems more interested in him. His friends explain she thinks he is gay and wants to take care of him. Lizewski goes along with this in an effort to spend time with her. Lizewski remains undeterred by his earlier setback, and ends up intervening in a gang fight outside a diner. Dressed in costume and using two modified night-sticks, he fights off three men. As the fight ends, a man who has been recording the event on his phone, asks Dave who he is, and he replies: "I'm Kick-Ass". The video is posted on the internet and soon becomes an internet phenomenon, making Kick-Ass a star overnight.
As Kick-Ass, Lizewski sets up a MySpace account, so people can contact him for help and is overwhelmed with responses. While spending time with Katie she admits she was being harassed by a lowlife drug dealer, and Lizewski convinces her to ask Kick-Ass for help. He investigates and ends up in an apartment full of violent lowlifes who try to kill him. He is rescued by a costumed, sword-wielding young girl named Hit-Girl, who kills all the attackers and then leaves to join her father, whose alias is Big Daddy. Hit-Girl jumps across the rooftops and tells Kick-Ass to follow her but he is afraid to jump, so they leave without him. Later Kick-Ass is visited at home by Hit-Girl and Big Daddy who have tracked him from his MySpace account. Hit-Girl and Big Daddy inform Kick-Ass that they can work together, and should he need help then he should set his MySpace status to "on vacation" and they will arrange a visit.
Meanwhile local crime syndicate leader Frank D'Amico (Mark Strong) hears of the deaths of many of his men, with many people believing that the new star, Kick-Ass, is responsible. In searching for Kick-Ass, D'Amico kills an impersonator who he believes is actually Kick-Ass. Running out of ideas, his son (Christopher Mintz-Plasse) offers a new idea. His idea involves him becoming the new superhero Red Mist, and enticing Kick-Ass into meeting him. At first, Red Mist attempts to lead Kick-Ass to a warehouse to be killed. They arrive at the warehouse to find it is on fire, and the men are dead. Red Mist retrieves secret surveillance footage and it is clear that Kick-Ass is not responsible for the attacks. Red Mist asks Kick-Ass to call upon the help of Hit-Girl and Big Daddy, and they arrange to meet at a safe house. Red Mist has led his father's gang right to them. As soon as they arrive, Hit-Girl is sitting on a window ledge and Red Mist shoots her, propelling her out of the window and on to the floor below. Kick-Ass and Big Daddy are captured and taken to a warehouse where the gangsters stage an internet broadcast where they intend to unmask and execute the heroes. Severely beaten and about to be set on fire, the lights are shot out and Hit-Girl starts a gun battle, killing off the villains, but a fire starts and Big Daddy is badly burnt. Before the battle concludes, he ends up dying of his injuries. Kick-Ass tries to convince Hit-Girl to quit but she is determined not to allow the death of her mother and father to be in vain and makes one last assault on the headquarters of Frank D'Amico.
Hit-Girl enters the building D'Amico is situated in and while posing as a lost schoolgirl, quickly disposes of the guards on the ground floor and moves to the elevator (where she suits up). Upon arrival, she quickly disposes of the majority of the guards, but runs out of ammunition and is forced to take cover in D'Amico's kitchen. Not willing to risk their lives with a direct confrontation with Hit-Girl, one of the henchmen grabs a bazooka stolen from Big Daddy's safe house earlier and prepares to fire, just as Kick-Ass shows up from outside the hotel with a jetpack with two Gatling guns, and opens fire on the henchmen (This is the first time Kick-Ass kills someone). After disposing of them, Kick-Ass and Hit-Girl move into D'Amico's office, and two separate fights ensue between Kick-Ass and Red Mist, and Hit-Girl and Frank D'Amico. While Kick-Ass and Red Mist fight until they knock each other out, Hit-Girl is overwhelmed by an older and stronger D'Amico. As D'Amico is about to shoot Hit-Girl, Kick-Ass appears with the bazooka from earlier and blasts D'Amico out the window, where he explodes in mid-air. Red Mist recovers and grabs his father's sword only to discover that Kick-Ass and Hit-Girl are already leaving. They tell each other their names and say goodbye.
Both Hit-Girl and Kick-Ass retire from crime fighting, with Hit-Girl living a normal life and attending the same school as Lizewski. Another wave of superheroes have been inspired by his exploits. Red Mist is shown donning a new mask and swearing vengeance, saying "Wait 'til they get a load of me".