In this chapter, we are introduced to Soji and her younger sister, nano. Soji's younger sister is called "nano" because she is younger than her brother, and because she has a crush on her older brother. We learn that the two of them are going to spend the day together at a festival, which is a high school festival. We also learn that Soji will not be able to come to the festival because of an illness, and that she will be accompanying her younger brother, who is named "soji" because he is older than her. We are also told that the festival will be the first time the two have met since they were little children, and they are both excited to meet their brother.