Takashi Natsume has been able to see youkai, Japanese monsters, his whole life. He inherited a book of youkai names from his grandmother, Reiko. These names give their owner power over the youkai, so he and his self-proclaimed bodyguard "Nyanko-sensei" spend their days returning them to their original owners. As Natsume finally finds a place where he feels welcome, he meets and says goodbye to new Youkai...

[Source: Crunchyroll]