Tatsuya is asked to join the team for the thesis competition as a last minute replacement. He would have preferred to stay out of the limelight, but the subject is of a particular interest so he joins reluctantly. Of course, nothing is simple for Tutsuya and now a group of thieves or spies is trying to steal something. Their exact goals are unclear, but they have infiltrated the school and seem to have some powerful backing. So while most of this first part of a 2-part arc is about high school life and interaction between the various characters, there is some action with the promise of more to come in Volume 7.
Volume 6 is a good addition to the series with a few good character developments, especially for some of the side characters. We do get to learn a bit about Tatsuya's family life and history. As with the earlier parts, I love the world building and how Tatsuya and his sister are powerful, intelligent and brave, but still have clear weaknesses and need their friends to compensate for those. There are no damsels in distress and you understand why people are friends with each other. Tatsuya is clearly not the centre of everybody around him, not even the women, and his male friends are not goofballs typical to the genre. Of course, the role and power of the characters is a bit much for high school students, but that is what you would expect for the genre, although here the author at least gave it some thought and limited it to some extend.
All in all, I greatly enjoyed reading it, even if it is a bit slow on action (which is fully compensated in volume 7 which is action packed to the extreme).
The cover is a bit misplaced in my opinion Honoka and Shizuku don't play that much of a role and it is a bit more grim then the stars and purple bubbles suggest. It is very much the first part of an arc, and the story is not finished until Volume 7, and although the ending is not a cliff-hanger, it is still very much not ended.