Dave Lizewski is an unnoticed high school student and comic book fan with a few friends and who lives alone with his father. His life is not very difficult and his personal trials not that overwhelming. However, one day he makes the simple decision to become a super-hero even though he has no powers or training.

After Kick-Ass' insane bravery inspires a new wave of self-made masked crusaders, led by the badass Colonel Stars and Stripes, our hero joins them on patrol. When these amateur superheroes are hunted down by Red Mist -- reborn as The Mother F%&*^r -- only the blade-wielding Hit Girl can prevent their annihilation. When we last saw junior assassin Hit Girl and young vigilante Kick-Ass, they were trying to live as normal teenagers Mindy and Dave. With graduation looming and uncertain what to do, Dave decides to start the world's first superhero team with Mindy. Unfortunately, when Mindy is busted for sneaking out as Hit Girl, she's forced to retire-leaving her to navigate the terrifying world of high-school mean girls on her own. With no one left to turn to, Dave joins forces with Justice Forever, run by a born-again ex-mobster named Colonel Stars and Stripes. Just as they start to make a real difference on the streets, the world's first super villain, The Mother F%&*^r, assembles his own evil league and puts a plan in motion to make Kick-Ass and Hit Girl pay for what they did to his dad. But there's only one problem with his scheme: If you mess with one member of Justice Forever, you mess with them all.