Osananajimi no Kanojo to Namaiki na Imouto o Bitch ni Shiteyatta Fuhaha (Game Version)

Two young girls go from sweet innocence to hardcore sluts. Starring imouto Misa and childhood friend Nodoka.

"My name is Yuuichi, and I have a little sister.
She's not just the smartest girl in her class, but the whole school.
No matter what I compare poorly to her.
My imouto -- Misa -- looks down on me now.
If I catch her eye she'll spew abuse at me.
Getting mistreated like that has built a black ball of misery inside me...
Someday I'll have my revenge. Someday."


[From DLsite English]