Natsume's Book of Friends volume 18 features story and art by Yuki Midorikawa.

A local exorcist has passed away, leaving behind a study packed with a lifetime of important yokai research. But his family are normal and don't know where he's hidden his workroom. Now all the exorcists in the area are on the hunt for the mysterious library. But Natsume can't decide what is more dangerous - letting the other exorcists find the collection or discovering it himself!