Well you can tell this is Oshimi first work. Probably the weakest he's done, yet still interesting.

So our main character is 30 years old, his wife is pregnant, and he's wondering what he's doing with his life. He begins to think back on all his past relationships, if you can call them that, and remembers in middle school a girl straddled him when the lights went out. So he for some reason has that on his mind as his 5 month old wife yells at him for not quitting smoking because...SMOKING KILLS YOU FUCKING DICK. Okay so I have no sympathy for this guy at the start. One day he's walking by a internet cafe and decides to stop by. Guess who he meets there? That girl from middle school. So they begin catching up but as they're about to leave there's a flood. And then boom, everything goes wrong.

I don't have to love a main character to enjoy the book I'm reading. so I got passed that but it was harder to like him the more I got into it. Especially when he's becoming a horn dog to this girl while his wife is at home, upset, with a baby in her belly. But then the story shifts more sci-fi and we get thrown into a weird place which I won't spoil. There's some shocking moments with the slow build up, and the ending is what the fuck. The dialogue can be pretty awful too, while the story itself can be interesting.

It's a conflicting manga, one I'm not sure I'd recommend. I believe his newer works are far better. But if want something weird, check it out. I will mention as a warning this does contain rape and some gruesome violence so be prepared. A 2.5-3 out of 5.