"I'm thinking of taking the entrance exam for medical school. It will make my mother feel at ease." Tsubaki is told of her future path by her son, with whom she has always lived in harmony. The son has always treasured his mother, and she also believed without a doubt that he was the most important to her. However, her mother had kept it a secret until now, but she was dating a man and was considering remarrying. "I wasn't the most important..." The son lashes out at his mother with intense jealousy and aroused lust. This awakens the mother's lust, and she becomes addicted to immoral acts.