The whole school is talking about Mariana Mendoza’s Halloween party, which is coming up on Friday. Mariana’s parties “are kind of legendary because her parents don’t care WHAT goes on, as long as it stays in the basement” (140). Greg has never been invited to one of these parties, and this year he is desperate to attend. However, because last year’s party got so out of control, her parents are only letting her invite students “who are in the school band with her” (141). 

Greg is not in the band, but Rowley is. Greg is convinced that if Rowley goes without him, he will be socially lost, so he decides to join the band to get invited. Mrs. Heffley is excited that Greg wants to “challenge [himself] and try something new” (142) but Mr. Heffley is skeptical. He argues that instruments cost a lot of money that he doesn’t want to spend if Greg isn’t going to stick with it. He brings up the time that they tried to get Greg into playing piano, which failed miserably: he never practiced and was not interested in learning. Mrs. Heffley insists that they just need to find the right instrument for Greg.