Rather than hang out with Sensei in her room, Chika invites him to walk with her to the Old District, where she went with Sensei before. Chika is going to look after her little sister. Sensei is surprised to learn that Yumi helps, but Chika says that Yumi is actually good with kids, and isn't the demon people think she is. Before they arrive, Chika warns Sensei that her sister has a compromised immune system and really bad asthma, making it important to be careful of her health. They go inside and Sensei meets Chika's sister, who is named Chinami. Chika and Yumi have after Chinami by themselves since Chika's mother passed away — Chinami shows Sensei a photo, which causes Chika to start crying. Sensei and Chinami get on well, and Sensei quickly comes to feel protective of her. Chinami tells Sensei to keep being nice to Chika.