Murakami is the first daughter in a family of two sisters. She is very pampered and loves her younger sibling. However, perhaps the younger brother understands that he is the only son in the family, so his personality is very disobedient and stubborn. One day, when he suddenly lost his life, he took his sister's phone and opened the photo album to masturbate. The older sister went to look for her phone and discovered her precious younger brother was doing immoral things. Instead of scolding him, Murakami encouraged him and let him practice with real people. In the following days, the two sisters were entwined with each other, continuously having incest everywhere in the house, regardless of whether their father accidentally caught them.