Natsume's Book of Friends the Movie: Ephemeral Bond

Takashi Natsume continues to return the names of the spirits that have been written in the "Book of Friends" he inherited from his grandmother, Reiko Natsume. While navigating between humans and youkai with his friend, pet, and bodyguard Nyanko-sensei, Natsume coincidentally reunites with an old classmate, Daisuke Yuuki. It brings back painful memories of a youkai from his past. Meanwhile, Natsume also becomes acquainted with Yorie Tsumura, a woman who knew Reiko and who happened to be in the memories of a youkai whose name he had returned. Yorie now lives a peaceful life with her only son, Mukuo. Spending time with this family comforts Natsume, but a mysterious youkai has been lurking in their town. On the way back from investigating with Natsume, Nyanko-sensei winds up getting himself into trouble that only Natsume and his friends—be they youkai or human—can help him out of.

Synopsis from Anime News Network