SORA-441 To protect her young sister Mana from her uncle with abnormal sexual desires, the older sister Kana offers herself as a substitute.

An old man who lives alone in the mountains... I wonder if I was looking forward to going every year because it is great nature. However, in fact, the uncle and the mother were paying the debt with their bodies without the young sisters knowing. She is her older sister Kana who can't read the situation, but her uncle taunts her younger sister Mana with obscene words like her favorite phrase. She comes to terms with her uncle's hopelessly disgusting tendencies as she tries to help her sister and mother. However, she gradually feels that her disgust... She gradually dominates Kana's body... She thinks of herself more than her sister. Rather than her mother….