my sisters are mine.

The protagonist, who is not on good terms with his parents, has carefully raised two of his real sisters.
However, one day, it is reported that the older sister, Kuon, has a boyfriend.On the surface, the protagonist is delighted.However, I was driven by complex thoughts in the bottom of my heart.
Even so, it was the main character who had put up with it for the happiness of his sister, but seeing the red sound that was dumped by her boyfriend, emotions explode.

"I'm the one who raised my sisters."
"I'm the only one who can make my sisters happy ......!」

The twisted thought of love explodes, and I commit a sister in the middle of the night.
This is when his parents find out, and the protagonist is disowned.

―・Aoba, a younger sister, comes to the main character, who has been living alone as the seasons change.
The protagonist, who was depressed every day when his parents took away his sister who raised him cute, thinks that he will take this opportunity to make Aoba his own thing.

"Bonds by blood relatives, etc., can not be trusted ...... what can be trusted, it is only a sexual connection ......"

The main character who has been completely distorted repeats ○ ○ until it becomes a prisoner of sex when it is for the happiness of 3 brothers and sisters.

両親と不仲である主人公は、実の妹ふたりを大切に育ててきた。
だがある日、上の妹・紅音 （くおん）に彼氏ができたと報告される。表面上は喜ぶ主人公。しかし、心の底では複雑な思いに駆られていた。
それでも妹の幸せのためだと我慢していた主人公だったが、彼氏に振られた紅音を見て、感情が爆発する。

「妹たちを育ててきたのは自分だ」
「妹たちを幸せにできるのは、俺だけだ……！」

愛するがゆえの歪んだ思いが爆発し、夜中に妹を犯してしまう。
そのことが両親にバレてしまい、主人公は勘当されることに。

――季節が巡り、ひとりで生活を送っていた主人公の元へ、下の妹・蒼羽 （あおは）がやって来た。
両親に可愛く育てた妹を奪われたと、日々鬱屈していた主人公は、これを機に蒼羽を自分のモノにしてしまおうと考える。

「血縁による絆など、信用できない……信用できるもの、それは性的な繋がりだけだ……」

すっかり歪んでしまった主人公は、兄妹3人の幸せのためだと、妹たちを性の虜になるまで○○を繰り返していく――。