This anime doesn't hide its taboo. No sir, its full blown incest. Unlike kiss x sis where they are not blood related and the story shoves that in your face on multiple occasions, Aki-Sora casually mentions. It doesn't try to justify that what they are doing is socially okay. It doesn't give a fuck.
The scenes are amazing. Nothing is shown of course, but its still amazing. Considering the fact that sex isn't just one pose and that's it, it varies from scene to scene, moment to moment. It has more to shown than soft porn bullshit with moving furniture.
Sora (the guy) is presented as a weak male that ALMOST resembles a female and even a couple of times is forced to dress like one. Almost all of the female characters are so masculine that this anime is a sort of gender power-play in a way. Depending on your taste, you might find this distasteful to a degree and I am compelled to understand why. Its almost always the females that initiate any sort of sexual action because Sora is just plain ashamed and embarrassed of even thinking about it.
I can't say it has a story, as it is on a day by day basis and it has little to show story wise. They are all going to school ( OF COURSE THEY ARE ) and there are some plots here and there, but they are minor. Mostly it revolves around emotional discovery of Sora, his two sisters and one of the sister's friend who also likes Sora but has no clue what is going on.
I highly recommend it to ecchi lovers that haven't already seen it.
IMO, you need an open mind for this because this is incest and the anime doesn't even try to hide it. Otherwise you'll just judge it.
