Chocolate Boy makes a bet with Wolfgang to not eat chocolate for 2 weeks, and in exchange, he'll get 10 pounds of chocolate. Wolfgang gets Mickey to keep an eye on him, to which he does and catches Chocolate Boy every time he tries to eat chocolate. Chocolate Boy goes to Arnold to help him get off chocolate, in which they take all the remaining chocolate out of his room. As 2 weeks go by, Chocolate Boy goes through withdrawal, including licking ants from the ground, which he thinks taste like chocolate. When the two weeks are up, Arnold congratulates him, but Wolfgang shows up and gives him the 10 pound bag, to which Arnold finds out it was a bet the whole time and is disappointed.
When Chocolate Boy finishes eating his bag, Wolfgang and his gang of 5th graders come to his spot and notice he's finished the bag. Wolfgang says he'll give him more chocolate if he does a dance. He eagerly does it and gets more chocolate, only to be taunted and humiliated by the 5th graders. In the dumpster, Chocolate Boy is looking for chocolate until he sees a mirror and sees Wolfgang and the other 5th graders laughing, and then sees them and himself as chocolate ice cream.
Chocolate Boy goes to Arnold's house and asks him to help him stop eating chocolate for good. Arnold's unsure at first, but once Chocolate Boy makes it clear that he's serious about quitting, since all he's doing is humiliating himself by turning into a (chocolate) clown, Arnold agrees to help. In the living room, Chocolate Boy is tied up in chair while Arnold shows a slide show of what bad things chocolate can do to him, but it ends up making Chocolate Boy wanting to eat more chocolate. Outside, they are in a sauna so Chocolate Boy can "sweat" the chocolate out of him, but this doesn't work. In the kitchen, Arnold gives Chocolate Boy carob, which is a substitute for chocolate, but it turns out Chocolate Boy's allergic to it and develops a rash. They try other foods like carrots, peppers and celery, but Chocolate Boy doesn't like them—while he likes the radishes Arnold gives him to try, he says that they just make him think about chocolate. Arnold then decides that they need to try harder.
Up in Arnold's room, it turns out that the duo has resorted to hypnosis to try and figure out why Chocolate Boy's so addicted to chocolate in the first place, figuring that there's some kind of psychological issue behind it. As it turns out, when Chocolate Boy was really little, his parents wouldn't let him have chocolate because they said it was bad for him—however, Chocolate Boy's nanny (who he really loved) would secretly give him chocolate despite what his parents said. But one day, when he came home from preschool, his nanny said she had to go to a faraway land called "Delaware," gave him a bag of chocolate, and told him "be good and be happy" and left. After she was gone, Chocolate Boy went up to his room and ate all the chocolate that his nanny had given. Arnold then deduces that the reason Chocolate Boy eats chocolate is because he uses it as a coping mechanism due to missing his nanny, which Chocolate Boy tearfully admits is true. Arnold assures him that it's okay that he misses his nanny, but points out that it's not like eating chocolate is going to bring her back and asks him what would his nanny think if she saw Chocolate Boy eating chocolate out of dumpsters and dancing for chocolate. Chocolate Boy responds she wouldn't like it because he's not good or happy, and Arnold follows up by saying he can be happy if he stops eating chocolate, which ultimately breaks his addiction.
At school, everyone hears the news and is shocked that Arnold helped Chocolate Boy stop eating chocolate. This also surprises Wolfgang when he offers Chocolate Boy chocolate, but Chocolate Boy refuses. Arnold congratulates Chocolate Boy, but soon sees that now he is addicted to radishes. Arnold thinks he's had enough, but Chocolate Boy refuses to put them away.