The story revolves around a junior-high student. Keita is your average, easy to relate to guy struggling to get his grades at a certain level, so he can go to the same school as his sisters. Yeah, his twin-sisters. Actually, they aren't blood related, but their parents married while they were still young. Now normally that wouldn't be much of a problem, but this time both are madly in love with him. Throughout the anime, they both try to win his heart, often causing him to fail at what is trying to. As the story continues, he gets more and more interested in them, and that even results in a few spicy scenes. Well...what am I saying? I guess you could say this anime has quite a bit borderline hentai scenes. Now don't think because of that, this anime is bad, because it isn't. It's very lighthearted and enjoyable, just as anime like this should be!
That said, the animation is great, unlike most (borderline) hentai anime. The characters and background are animated well, and I'm quite fond of the colouring. I haven't found many scenes where characters are moving awkwardly, or anything alike. Sometimes though, especially when scenes get a little more sexual, you'll notice the occasional flaw, or at least the really hentai-like kissing. But seeing there's more than enough good animation to make op for that, i don't really mind at all. And I'm sure most people considering to watch this one wouldn't either.
Both OP en ED are incredibly catchy. After a few episodes i found myself humming the ED while showering. I can't say I'm really proud of that, but you get my point. The voice acting is pretty good. The two girls are equipped with the required -and well preformed- "little girl" voices, and just hearing Ken Takeuchi voicing Keita is usually more then enough to feel his awkwardness. I saw the OVA before, but still wasn't expecting much of the voice acting, but i can say I'm positively surprised.
The characters aren't special, but certainly not bad. Keita is the typical "harem-anime lead", spending most of his time fantasizing about the girls, or doing things with them he normally fantasizes about. Ako is the mature sister, who cooks for the family, has good grades etc. Riko is a more of a childish and playful type. Although you'll sometimes ask yourself what their differences are, they are especially visable when seducing Keita.
To fill in some of the blank spots, there are some filler characters. I must say they are pretty well made. There's a group of guys who represent Keita's school friends. They constantly point out Keita's luck to have two hot sisters to love him, often causing Keita to fantasize about his sisters himself. There is also a loli who seems to have a crush on him. And we have Ako's teacher, who's also aforementioned loli's sister, an Otaku who tries to make Keita, Ako and Riko see their incestuous tendencies, are wrong. Their parents also have a small role. They're very stereotypical parents, except for the fact that dad encourages their love, and especially Keita's manliness. Last but not least we have Miharu Mikuni, a shy, glasses wearing, big-titted girl, who does the best job providing us with some interesting comedy.
Overall I think this is a more than decent anime. The main reason to watch this would be the hot brother-sister action you might be into, but i mostly decided to finish it because it just is a very entertaining anime.
So, if you're looking for an easy going anime, and wouldn't mind some interesting sexual scenes, this might be the anime you're looking for.