In chapter twenty-one Stargirl shows Leo the different places where she gets her information about people, so she knows to whom she should send cards or gifts. She reads the daily paper, especially the fillers, which are the small articles meant to take up space. She also checks bulletin boards. At the mall they play a game where they follow someone for fifteen minutes to try to decide what type of card the person could use. While following a woman, Stargirl dropped coins all over the mall. She said she hated having jangly change in her pocket, and she loved seeing young children find it.

Chapter twenty-two has Leo visiting Stargirl's house, which is surprisingly normal. He thought her room would have piles of supplies to make cards, but she said she keeps that kind of stuff in her office. On her shelf she keeps something called her happy wagon, which has twenty pebbles that she moves in and out of the wagon depending on her level of happiness. Leo noticed it currently contained seventeen, which is the happiest that she has ever been. She said it once got down to three pebbles. She pointed to a little boy across the street named Peter Sinkowitz, who is five years old. Stargirl takes pictures of him and writes things down that she sees him do in a biography that she's creating for him. She plans to give it to his mother to give to him when he's older. Leo seemed to be jealous of the attention that Stargirl was paying to Peter, so she leaned over and kissed him.

In chapter twenty-three Leo continues to endure the shunning at school. He thought about the question from Senor Saguaro about whose affection he valued more, and he resented that he had to decide. He wanted affection from Stargirl and attention from everyone else, and he didn't understand why he couldn't have it both ways.

Chapter twenty-four begins with whispers in the hall about the Roadrunner bulletin board in the courtyard. Leo looked out his classroom window second period and saw a bed sheet hung on the board with big letters saying "Stargirl loves Leo." At first he felt elated but then immediately felt embarrassed. At lunch he turned to look at her, and she blew a kiss at him. Later, when he looked in the courtyard, he saw someone had torn down the sheet. Stargirl ran up to Leo to ask him what he thought of it. He wasn't sure what to say. She sat Cinnamon on his shoulder, teasing him, and he swept him off and sent him flying then walked away.

The next day Leo was walking through the courtyard, and he saw a kid named Renshaw. Leo called out his name, and Renshaw didn't acknowledge him at all. When Leo asked Kevin what he did, Kevin replied that Leo knew what he did. He had linked himself to an unpopular person, which was his crime.

In chapter twenty-five, which took place a few days later, Stargirl stopped Leo to ask him if they were breaking up. He said he didn't want to, but something has to change. He's surprised that it doesn't bother her that people don't talk to her. She claims that Dori, her family, and Leo all talk to her. He says he can't believe she doesn't care what people think. Leo says he feels in touch with people; he's one of them. He accidentally called her Susan as he becomes frustrated trying to explain that she should care what other people think, that people belong to groups that tend to behave the same way, that she should care because nobody likes her. He felt bad saying it, but she needed to understand. Then two days later, she vanished.