Natsume continued returning the names of spirits that had been written in the Yuujinchou (Book of Friends) that his grandmother Reiko collected. Nyanko-sensei, a powerful spirit that took the form of a chubby cat, remained to protect Natsume from harmful spirits. in the earlier 2 seasons, Natsume wasn't able to make any human friends, only spirits. but since the third season, Natsume successfully made some human friends. which led to some conflicts that he had to decide whose side he was on.
having the ability to see demons, Natsume's everyday life was something different and easily became attractive, even after 3 seasons. the forth season, like its previous installments, were all told in a very simple and realistic manner. after each story, we often find ourselves having strong emotional connection with the characters. even when they appeared for the first time, a clear background will be shown, letting us know its origin, thus able to engage ourselves in its trouble.