Megs Pepper has been grounded! But she can't miss San Pimento's ComicCon and a chance to meet her favorite superhero, Diana Pence the Unstoppable Unicorn Woman. So Megs dons a makeshift costume and sneaks out of the house. And when she foils a would-be purse snatcher, Diana makes Megs her new sidekick. Things are looking extra-super until a villain called the Poker shows up and challenges Megs and her newfound heroism. It'll take Megs, Diana, and all of the Peppers with their truly terrifying superhero alter egos to take down this super baddie once and for all.