"Karin, Shizuka. If you report this sexual abuse, our family will fall apart?" one day, our mother decided to remarry. The father of her new husband had a somehow unpleasant atmosphere. He was looking at us sisters with lecherous eyes. Perhaps because our mother was there, he didn't touch us. The worst life. One day, the father who always takes the same train to school touched our butts and crotches. We were treated as he pleased while our mother wasn't looking, and we were about to cry, but somehow our lower bodies were twitching. We sisters, who hate our stepfather to death, began to secretly be violated and go crazy with sexual abuse on the train... Sexual abuse is, no, it might not be bad...