Takashi Natsume has grown accustomed to his interactions with youkai thanks to the Book of Friends, which collects the names of youkai who have signed contracts with his grandmother, Reiko Natsume. Natsume has a greater understanding of the youkai, Reiko, and himself as a result of these experiences. The Book of Friends is a potent tool for controlling youkai, and it is sought after by both youkai and exorcists. Natsume simply wants to go about his regular existence in peace, but he is frequently interrupted by these encounters. Natsume must learn more about the book and the realm of exorcism, as well as begin to open his heart to people who may aid him, if he is to be free of this anguish.