Aoi is the first daughter in a family of two sisters, she is very pampered and loves her younger brother. However, perhaps the younger brother understands that he is the only son in the family, so his personality is very unruly and stubborn. One day, when he suddenly lost his life, his cock took her phone and opened the photo album to masturbate. The sister went to look for her phone and discovered that her brother was doing a dirty trick. Instead of scolding, Aoi shows encouragement and lets her practice with real people. In the days that followed, the two sisters were entangled together, constantly incest everywhere in the house, despite the fact that the father accidentally caught them.