Very disjointed thoughts about this episode:
Wow, that was a shocker ending! The Ariake3 had already come to the conclusion that Togami-tei's owner killed their parents, but then in comes the wife of Shizuna's biological father and tells that her husband was the killer. I don't know what to believe, but I think next episode is going to reveal some more of the mystery.
However, I still think that the woman just suspected her husband of being the killer, since most of the evidence seems to point towards Togami Sr. And his own suspicious behaviour (getting upset about the hayashi rice mention, forbidding his son to recreate the recipe) just makes him look guiltier than ever.
I liked the more serious tone of this episode and the furthering of the mystery plot. The humour and the hunt for the killer were in a better balance than in some of the previous episodes. Of course, there were still some funny details, like the detective getting a bootleg copy of the porn disc and going out to party with George and Taisuke. Or that final scene for the Postit guy story.
I loved that slight smirk on Ryo's face when the Postit guy was ranting on about his eternal love.
I also loved Koichi's reaction when Togami Jr. told he had held Shii's hand and was hoping to get rid of his virginity with her... Even though there are some hints that he might feel more than just brotherly love for her, you could still interprete most of his reactions as those of a very protective older brother. Koichi has, after all, been looking after his two younger siblings (whether blood related or not) ever since their parents were murdered.
"No, it was my perverted feelings."
Shizuna looked genuinely happy when she was talking with Togami and planning on going out with him. She herself looked a bit shocked when she saw her own happy expression in the mirror and had to remind herself that he is the son of their enemy.
Weren't there hints in the drama promos that she will fall in love with the son of their enemy? Looks very much like it's happening here.
I thought it very interesting how the younger detective told Koichi that Kashiwabara was mixing his feelings about his own son with the Ariake kids. It had been shown to the viewers that the case was important to him and that he contacted Koichi right after the death of his son, but the three siblings didn't really know that before this.
The case had been open so long already, so they felt that they couldn't really trust the police to find the murderer and had to do it themselves. But it looks like this might slightly change their plans a bit, since they are considering of maybe accepting some help from Kashiwabara and revealing to him some of their findings. We'll just have to wait and see what happens...