Max's first year of middle school hasn't been easy. Eighth-grade hotshot Johnny Pro torments Max constantly, for no other reason than Max is fat and an easy target. Max wishes he could fight back, but he doesn't want to hurt Johnny... just make him feel the way Max feels. In desperation, Max writes to the only person he thinks will understand: imprisoned supervillain Master Plan, a "gentleman of size." To his surprise, Master Plan wants to help! He suggests a way for Max to get even with Johnny Pro, and change how the other kids at school see them both. And it works! When Master Plan's help pays off for Max in ways he couldn't have imagined, he starts gaining confidence--enough to finally talk to Marina, the girl he likes in class who shares his passion for baking. With Master Plan in his corner, anything seems possible... but is there a price to pay for the supervillain's help?