Natsume meets a yokai couple whom his grandmother had met and who specialize in making sake cups, particularly sake cups that add glorious tastes to whatever is drunk from them but then turn to dust after one night.
Natsume finds a town that had been submerged in water; Natsume gets possessed by a yokai and falls unconscious. Tarusaru informs Natsume about a festival and a Yukata that can turn a spirit into a human for a day.
Natsume inherited "The Book of Friends" from Reiko, his grandmother, and decides to return the name to the spirits. A spirit Tsuyugami come to see him soon, to return his name. But the page with his name had stuck to the next page.
A teenage boy, Takashi Natsume has had the ability to see spirits, but he hasn't known the way of dealing with them. One day, he is chased by a spirit, and run into a shrine. Then he encounters another spirit in Chinese-lucky-cat shape.
Natsume participates "trial of courage" in the class at the abandoned school building where a spirit has appeared. The class president Sasada is vaguely aware of Natsume's secret.