Every day spent with kind friends is worth cherishing - a beautiful and illusory story of people and monsters. Natsume Takashi, a boy who has been able to see monsters since he was a child, inherited his grandmother Reiko's legacy "Friends' Book" and began to return the names of the monsters bound in the Friends' Book with the cat teacher who calls himself a bodyguard. Natsume, who began to explore his own way forward by contacting monsters and the people related to them, tried to protect his important days with the help of friends who communicated with him.