Natsume decides to tell Natori about his secret, when the search for the seal room is over...

A competition is opened to search for a famous researcher's sealed room. The prize are his research books, and many exorcists are gathered. Natori is invited, Natsume wants to help as this might mean finding something that might let him find information about the Book of Friends.

After a flood occurs on Four Mask Hill during Natsume's summer school session, a mask randomly appearing in the school worries Natsume.

Natsume talks to a teenage boy at the station, who turns out to be a youkai that left a human because of their feelings for one another. The boy wants to find her because he received a wedding invitation.

Natsume is surprised when a youkai comes to seek Reiko in gratitude. Years ago, the youkai's to-be-bride received freedom from her help, and now is about to be wed. They invite Natsume to the wedding.

This episode shows how Natsume first befriended Nishimura and Kitamoto, along with a better look at their family lives and point of view.

Natsume and Natori discover that the youkai shiki (demon servants and friends) of Takuma Yusuke have been trying to bring misfortune into the house.

Natsume meets Tsukiko, a daughter of an exorcist named Takuma Yousuke who has recently lost his ability to see or hear youkai. Because she lacks the ability to see youkai, she asked Natori to check around the house because she feels something is wrong and a youkai may be out to hurt her father.

Natsume's old classmate Shibata (from "False Friend" / "Itsuwari no Yūjin" (偽りの友人)) calls. Natsume visit Shibata together with Tanuma, where Shibata tells them about the "Doll Mansion of Sotogi". A youkai from the mansion later attacks them.

Natsume helps a rock washer look for his apprentice who has stopped writing him.

A yokai known as "The Days Eater," turns Natsume back to a young child. Nyanko-sensei enlists the aid of Tanuma and Taki.