In the book, Love, Stargirl, Leo meets a most unusual girl. Her real name isn't Stargirl, but her mother and father have allowed her to choose her own name. Stargirl isn't like the other girls at school. She is true to her own nature and seems almost innocent when it comes to dealing with social norms. For a while this is completely enthralling to Leo and he finds himself falling in love with Stargirl. When writing an additional chapter to this book, one should keep in mind the characters and what they would likely do and how they would react in certain situations. You could write about the necktie and how his friends react to it, or that he makes something for Stargirl in return. He could have a secret hiding spot, just like Stargirl has in the desert, and he shares that with her. Or, maybe he's kept a journal, and he shares what is in that journal with her.