Natsume's secret is found out by Sasada, the class president, during the "Trial of Courage." She asks for his help to find the spirit that lives in the abandoned school. Natsume denies the fact that he can see anything, but she won't take no for an answer. Meanwhile, the spirit, Shigure, captures the rest of their school mates, in fury of the school being torn down...

Natsume is cursed by an evil spirit which is sealed to a tree. Not wanting to trouble his adoptive family, he decided to run away from home.