Dave/Kick-Ass and Mindy/Hit Girl (Chloe Grace Moretz) are about to graduate high school and become a crime-fighting duo when their noble plans are foiled by Mindy's strict parents. Now, as Mindy hangs up her Hit Girl uniform and navigates the treacherous high-school social scene, Kick-Ass begins patrolling the streets with Justice Forever, a fearless group of urban watchdogs fronted by former mob thug Colonel Stars and Stripes (Jim Carrey).
They've got the criminal element on the run when Chris D'Amico lays his Red Mist persona to rest, and reemerges as The Mother F**ker, a powerful criminal mastermind with a loyal legion of henchmen.
The Mother F**ker is determined to avenge the death of his late father, who previously perished at the hands of Kick-Ass and Hit Girl. Now, as The Mother F**ker and his minions begin targeting the members of Justice Forever, Hit Girl realizes that the only way to save Kick-Ass and his new friends is to emerge from her forced retirement, and fight back with everything she's got.