The Good For You Party has prohibited sweets like chocolate during their political rule. This ban is strictly enforced with force if necessary. Two teenage boys, Smudger and Huntley, are determined to break the rules and enjoy chocolate again. They embark on a quest to find illegal chocolate vendors, eventually setting up their own clandestine distribution network for sweets.
Chocolate Underground is based on the the British childrens novel Bootleg by Alex Shearer.