Kiriya Hakushakuke no Roku Shimai

One day, Daisuke, a reporter, visits an old Western house on the hill. There are Sumi, the owner of the house, and her five daughters. "You are a selected man. Yes, you can make a baby with my daughters and get everything here." Though Daisuke still can't believe it, he starts staying at her house. Erotic and deep relationship with the sisters. What is the secret of this house? What will happen to Daisuke?