Satsuki is a bright and lively girl that always shines like the sun.
Yukari is a introverted girl who is as obedient as a doll.
They're so different that it wasn't until I was dating Satsuki in college that I realized that they were twin sisters.

I never disliked Satsuki. It's hard to explain it, but it seemed like she was just always nearby, and she just became like air in the way I took her for granted.
Right during that time Yukari showed up in my life and she was fresh and new in every sense of the word.
It never seemed like I was really lovers with Yukari or anything, she just happened to be a girl of convenience who would come every time I called.

Naturally I tried to be careful to make sure Satsuki didn't find out, but now I think it's turning into an even more interesting relationship.

[From DLsite English]