Eriko of the Younger Sister which came to the house of Elderly Sister, the Chisato to play. Were four people swelling for a reencounter after a long absence, but son, Tatsuya of Eriko witnesses Masturbation of the Chisato in just an opportunity. The Chisato attacks the nephew kid on greed, and the gear which has begun to be out of order from there develops to large Incest with two sets of Parent and child being mixed and confused each other.
