The two sisters Yuki and Ayame share with you a piece of life in Slice of Venture Origins. The story begins in a train, the sisters travel to meet a part of their family living in the japanese countryside. Soon, they discover accidentally that the whole family has many secrets to hide. Witnesses of incestful relationships, Yuki and Ayame become more and more curious! For example, the youngest sister seems obsessed by that DVD showing a girl loving sex with animals… Moreover, a touch of fantasy appears with a succubus living in the depths of the family house. In a few time, Yuki and Ayame meet many people with a life turning around sex. Finally, how these two weeks among that family will affect the two girls and their lives?