Ryousuke has lived in poor circumstances, and it turned him strange.
His father went "on business" overseas, scattering the family for more than 6 years.
Now he's coming home suddenly... to see the twin sisters Airi and Yuuri.
That trash! That sh*tbird! How dare he show up like this, and ignore his son?

It's with this anger that you, Ryousuke, turn all your strength against the girls.
These sisters who are so superior and command familial attention,
it's not satisfying to merely violate their maidenheads.
It's not enough to douse their radiant charms.
You want to pollute them much more deeply.

[From DLsite English]