Takashi Natsume inherits his grandmother's ability to see Yokai, invisible spirits. He also inherits a book she made where she had captured their names. The Yokai come after him, wanting their names back. He befriends Nyanko Sensei, a Yokai who looks like a ceramic cat who agrees to help him return the names to the Yokai in return for getting the Book of Friends when Takashi dies.