夏目貴志は、幼いころから妖怪が見える少年。祖母レイコから「友人帳」を受け継いで以来、自称用心棒のニャンコ先生とともに、友人帳に縛られた妖怪たちに名前を返す日々を送っていた。さまざまな妖怪や人々と出会ううちに、大切なものが増えていく。誰かを守るために秘密を守ることが正しいのかと自問しながら、少しずつ勇気を出して友情を深めていく。
Takashi Natsume is a boy who's been able to see youkai ever since he was a child. Ever since he inherited the "Book of Friends" from his grandmother Reiko, he and his self-proclaimed bodyguard Nyanko-sensei have spent their days returning names to the youkai who are bound by the book. As he meets the different youkai and people, he finds himself with many more things that he cares about. He wonders whether it's right to keep secrets to protect someone as little by little he works up the courage to build even more friendships.