Comic book geek Dave sets out to become Kick-Ass, a real-life superhero. Big Daddy and Hit-Girl attempt to dismantle the underworld empire of mob boss Frank D'Amico, when Kick-Ass gets involved.

Kick-Ass, a superhero in high school, is forced to join new heroes and old allies in order to fight his old nemesis, Red Mist, when he forms a team of supervillains to get revenge against him.