At the end of volume 4 Kaori confessed her love to Suimei, but Suimei was not in a position to give her an answer (not that there is any doubt of his answer even to Kaori but there is always that nervousness). Now they are about to finally meet again, but instead of getting some time alone, they end up in the middle of a mess when a fox threaten to destroy the bookshop out of some kind of misplaced blame. The fox's daughter fell in love with a human, and it were those hated books that pushed her into the human world.
Like previous volumes, family (especially fatherhood) and mortality are the central themes of the book. Mix in old Japanese folklore and literature and you end with the kind of interesting story that we are used to. There are many kinds of fathers, and while most act out of love for their daughter, that in itself is not enough. The extra details we get on Noname and Tamaki's history are a great bonus. And Kaori and Suimei are cute together, especially their clumsiness at the end.
The plot itself was a bit convoluted, plots within plots within plots, trying a bit too hard to fit various famous Japanese stories in regards to foxes and tanuki and than adding Tamaki's end purpose on top. Nothing major, especially considering it fits the world the series set up with spirits being influenced by the stories told about them, just that the twist lacked a bit of an impact for me as a result.
So, a story great for its world building, characters and its integration of Japanese folklore (at least as far as I can judge considering my lack of deep knowledge on the subject), it was a great read and I am looking forward to the next part and its focus on the main father in the series.