Hi Ran! ^^/
Yes, it's a nice set, I really wanted to buy it because I love this series, the characters, the story, and the anime character design is wonderful.
I'm not really good with summary, and above all to explain it in english, so sorry if I took it from the web:
Natsume Takashi has the ability to see spirits, which he has long kept secret. However, once he inherits a strange book that belonged to his deceased grandmother, Reiko, he discovers the reason why spirits surround him. Containing the names of these spirits, a binding contract was formed between the spirits and the owner of the book. Now, Natsume is determined to free the spirits and dissolve the contracts. With the help of a spirit cat, his days are filled trying to return the names to these spirits.