In this volume the author spends a lot of time building the background of Takahisa and Princess Liliana. Quite slow but steady. At the end the author surprised with something not very creative. Is strange as the author since volume 1, introduce original plots and characters in a brilliant form. But here, he ends with a Labyrinth and a quite fast dungeon delving, with the standard tropes, some goblins, orcs and minotaurs. A new antagonist appears at the end, but poorly described. It looks like the author just tries to introduce new plots to keep the serie running, but in this volume nothing new or creative was introduced.
While the overall plot did not advance all that much in this volume, it did contain one of the best depictions I've seen in a light-novel of a Narcissistic Abuser, particularly the way they try and gaslight people. It also shows the importance of having a good support system; if Aki and Miharu did not have their friends (particularly Satsuki), things would have gone very differently.