The sudden tragedy which attacks the girl "Yuki" which grew up in peaceful families poorly! ！A grandfather and father and the older brother love lovely daughter Yuki. One day Younger Sister, the Yuki that the Pranks which is Sex is done by the older brother who played together. However, she cannot possibly understand even that it is the act that is not permitted. While I have her massage it, father who came home when Yuki lies down feels indecent, and insert ma ○ coni unreasonableness spear undeveloped at last….
