Natsume encounters some strange, monkey-mask wearing demons while out in a forest. They want the book of friends, and start physically threatening him until Natsume is saved by Nyanko-Sensei.
A spirit Yobiko asks Natsume to call a spirit Karikami using "The Book of Friends". Yobiko wants to be able to read old unreadable letters with Karikami's ability.
In the town Natsume used to live in, a girl recalls Natsume. She remembers his strange actions and wanted to understand him. Meanwhile, Natsume encounters a small Youkai which reminds him of the same girl and town.
Natori is tasked with the job of finding and breaking the seal of Houzukigami, a god that was to participate in the Moon-Splitting Festival done every 10 years against Fuzukigami, another god.
Natsume is pretending to be the god Houzukigami, so the moon splitting festival will end with a victory and the mountain will not be ruined. Winning the contest will not be easy, but with help from Natori he will find the way.
Natsume looks back at a photo of his parents, and old wounds are reopened. Natsume is having a fun day with his friends, but all of a sudden he gets a phone call.
Natsume, accompanied by Nyanko-sensei, set out to visit his old home. He visits a relative to pick up the key to the house, but is being followed by a youkai who wants him to draw a mouth for it.
