This series is about the relationship between an older and a younger sister and their half-brother. I don't know what hell I'll go to if I say that, but the show is trash, but trash that I had to watch until the end. In addition, they are not blood relatives and over 18, that makes everything OK, as usual ?!

story
Natsuo is in love with his teacher Hina. Then he gets to know Rui who offers him to sleep with her and he agrees because she looks like his teacher. Then his father, who has been looking after him alone since his mother's death, tells him that he has fallen in love again and wants to get married again. When Natsuo meets his stepmother, it turns out that his teacher and the girl he slept with are their daughters, which in turn means that both are sisters and will become his stepsisters. However, when all the children agree to the new partnership because their parents deserve to be happy, they all move in together. For the reasons just mentioned, living together is not exactly easy for the three siblings. You ask, that was a long summary, but isn't that already spoiling? No, because none of these events even include the entire first episode. And that's exactly how it continues with a total of 12 episodes.

Animation and music
We are far from the quality of Kyoto animation here. The backgrounds are nice, but the rest is mostly kept quite simple (shortly before the end, the quality drops again significantly). That might bother one or the other, but I was never torn from the story because of the animation. The characters conveyed the story and the emotions that were needed and as with games I have to admit that I enjoy beautiful animation, but not everything has to be a Triple A title with perfect light and water reflections or something similar. If the story fits and the animation conveys what it is supposed to, I'm happy. As far as the music is concerned, I also have to say that if I'm caught up in the story and I don't notice the music (especially not negatively) then the music did everything right. It would be too much to ask for a melody like in Clannad in every series that evokes all emotions from the series at the push of a button. In addition, the series has a great opening from Minami (I thought it was YUI at first because the voice sounds similar but the opening is great anyway). You can not ask for more.

Characters
As already mentioned, we have Natsuo, Imouto Rui and his older sister and teacher Hina. These of course have parents whose names are irrelevant, Natsuo's friend Fumiya, the lonely Momo and the chairwoman of the book club. That could sound like the cast of a harem with standard girls and clichés, but actually everyone except Natsuo and his sisters are just there to keep the story varied. In principle, apart from Natsuo (straightforward, honest, protective instinct) there are no stereotypes but credible individual people who are thrown into situations and have to live with their consequences. Is it unrealistic that a boy who is keen on his teacher and likes books is ensnared by so many women? I didn't want an anime about a nerd who just sits in front of the computer and doesn't experience anything and thus doesn't get to know anyone, but I wouldn't watch either.

Conclusion:
On the one hand I said that I 'had to' watch the series to the end, on the other hand I called the series trash. First of all, what do I mean by trash. In contrast to Nana, for example, this was not a great drama, but mostly felt like a soap opera on television on an anime level. Dramatic events happened every 5 minutes and I always thought to myself 'No', 'You can't', etc. That's why the series is trash from my point of view. Just like television productions and reality TV. And now we have the forbidden love (intended allusion) of teacher / pupil / step-sibling / Imouto. And considering how quickly I usually break off a series, I'll try to briefly explain how I not only managed to get through the first episode despite the subject and story, but also gave myself like a drug all night long. And the answer is not easy. If it were because the subject is taboo, I would watch other shows of the same type, but I don't. The characters are not clichés and some of them feel real. You get the feeling that everyone just got into a situation for which no one can do anything. The relationship of the three started before they knew they were going to be a family and during all of this one always has the feeling that the person is acting according to his character. But if I had to defend every conversation to the effect that a real person would act like that, I would not get very far. It is not a Harem Girl of the Week series, it keeps moving and consequences have to be dealt with until the end. In the end, I found the characters likeable and was able to get involved with them, wanted to know what happened next. I think that's the selling point in the end. It's trash, but the characters are personable enough to carry the show. But check out the first episode. There is nothing that unfolds or changes greatly. What you get in the first episode is what you can expect.