Sue Ellen loses her diary in the library. Muffy, Francine, Binky, and Arthur find it, and think that it contains her opinions on them and whether to open it or return it unread. Arthur sneaks into the dump to retrieve a wheel for his school project, but accidentally cuts his knee on a sharp can. He hides the injury and makes D.W. promise not to tell anyone because he is not allowed to go to the dump, but D.W tries to convince him, with Brain's help, that he has to confess to his parents before his injury gets worse.