It was made by Yuzu in in order to help her on her date with Mei.. Unfortunately, Mei found it and sits at used it instead. Mei follows the notes throughout their first date Yuzu felt like the notes are geting in the way of their date so she threw it away. But, much to her surprise, Mei run's after it and revealed that unlike Yuzu, she doesn't know what to do on their date. This confession then led into Yuzu laughing at Mei.Mei later used it again to help Yuzu out of her depressed state of finding out that not everyone will approve her's and Mei's relationshipMei writes in the book to encourage Yuzu no matter what hardship may happen in the future it shouldn't stop you from being who you are.