Toshiyo lives with her husband and son. One day, her son, who had been suffering from workplace bullying, tearfully confided in her, saying, "I've reached my limit. I don't want to go to work anymore." While her husband harshly told him, "Stop being weak and go to work," Toshiyo couldn't help but coddle him. Around this time, the son accidentally witnessed his parents having sex. Seeing his mother appear so pleasured while he was in pain, he felt a mix of anger and arousal—marking the beginning of a twisted change.