Haitoku no Shoujo / Depraved Family

Hiroko is a young and beautiful teacher who gives private lessons at home. This time she came to a huge mansion to teach a girl named Yukki. The introduction went well and soon the first introductory lesson was to begin. However, this did not happen and Hiroko lost consciousness after tasting the tea served by Yukki's sister. After a while, the girl regains consciousness and realizes that she is chained to the bed completely naked, and the two sisters, Yukki and Shizuki, are using her body as a sex toy. Hiroko learns the terrible secret of this family. Can she escape or will she forever remain a toy in the hands of depraved girls?