The lead character of the story is a 12-year-old girl named Karen Newman. Karen is the middle child in her family and is unfortunately (or maybe fortunately for her) not her parents' favorite. She has an older brother named Jeff (age 14; her mother's favorite) and a younger sister named Amy (age 6; her father's favorite).
Karen's world seems to be crumbling down before her eyes. She is led to believe that marriage only causes heartache and pain, and so she decides that she will never marry. Just before she entered sixth grade, she was overjoyed that she was placed in the class of a teacher that she desperately wanted to have; her hopes were shattered when she discovered that the teacher got married the summer before and has turned into a "witch." Her parents act like they don't love each other anymore; the only ways that they communicate is by arguing and fighting over every possible situation. Eventually, her father moves out of the family's house; when he announces his plans to go to Las Vegas to file for divorce, her mother is very happy. Karen's brother Jeff runs away after he finds out about his dad going to Las Vegas. Their father stays home to find Jeff, so he is unable to go to Las Vegas. Karen tries every possible way to stop the divorce from happening, including sending anniversary cards and pretending to be ill.