Suzume Akamatsu works at a library in Uwajima, Ehime Prefecture. She delivers books by riding a bicycle. Through her work, Suzume grows as a person.

Sin is a rock star. He has an amazingly loud voice with a range of four octaves. His secret is that he has created his voice through a method of vocal cord doping. His voice is now teetering on the edge, due to side effects from the vocal cord doping. Around this time, Sin meets Fūka, who is a street musician. When Fūka sings, her voice is so small. Due to Fūka, Sin looks back upon his past.

Natsume has been busy, navigating between humans and Yokai when he coincidentally reunites with an old classmate, Yuki. It brings back painful memories of a certain Yokai. Meanwhile, Natsume also became acquainted with Yorie Tsumura, a woman in the memories of a Yokai whose name he had returned. Yorie knew much about Reiko, but now lived a peaceful life with her only son, Mukuo. Being with this family was comforting for Natsume, but apparently a mysterious Yokai has been lurking in their town. On the way back from investigating, a “Yokai seed” that had latched itself to Nyanko Sensei drops into the Fujiwaras’ garden and grows overnight into a fruit tree. When Nyanko Sensei eats a fruit that is somehow shaped like himself, he suddenly splits into three!