One day, Reiko asked her son to bring in the laundry and went out shopping. The son picked up Reiko's panties and smelled them. He remembered the couple's lovemaking that he had secretly spied on the night before. That night, the son masturbated while smelling his mother's panties. When the son left the room, he heard a voice. He looked over and found Reiko masturbating. The next day, Reiko was cleaning. The son saw Reiko's butt and remembered masturbating and became excited. Unable to hold back, the son attacked Reiko...