This patch was included in another gallery on this site, but the CGs weren't split. Had an unpleasant time manually separating the CGs; I don't know how the other guys did it.
Scenes labelled "VS" are variations where Shieri is asleep.
Damn, Shieri is really hot. I've only seen the hentai though so I'm curious why there is a deflation tag? Haven't seen any after a quick glance here, nor is she shown to be a virgin in the animation.
So this game's plot is suuuuuuuper convoluted for a fucking nukige, so let's break it down real quick.
The main character is Haibara Hikomori, part of the very rich and old Haibara family His grandfather, Aizen, acts as patriarch and is often seen with his adopted daughter and personal maid, Shieri. Also living in their mansion is Shiho, the widow of Aizen's son and Hikomori's uncle Hiroshi, along with Shiho's three daughters Reina, Aya, and Narumi. Also present is Reina's fiance Koji and Aya's schoolmate Kaede.
As it turns out, the Haibara family has two major secrets. The first is that they've developed a drug that extends their lifespan, and the second is that they've undergone generations of inbreeding to keep their bloodline pure. Hikomori is the product of Aizen's rape of his daughter Megumi, while Shiho was forced to bear Aizen's three children as well. Ten years before the events of the game, Hiroshi and Megumi tried to escape Aizen but fell off a cliff, killing Megumi. Hiroshi was forced to undergo cosmetic surgery to become Aizen's body double, and the Aizen you see throughout the game is actually Hiroshi. Meanwhile, Aizen kidnapped a woman and hypnotized her into thinking she was Megumi to... torment... Hiroshi...? Yeah, I don't get it either. Both Hiroshi and Shieri are convinced that Megumi survived the fall and also underwent cosmetic surgery to become Shieri. Ten years later, Reina falls in love with Koji, who is promptly killed and replaced by Aizen so that he can continue his inbreeding.