Six months have passed since Mitsuyo's divorce in middle age. She now lives with her daughter and son-in-law, content with her life. However, Mitsuyo has a secret. Half a year ago, when the divorce was finalized, she was drinking to celebrate. Her son-in-law came home, and she hugged him, kissed him, and had sex with him, telling him to keep it quiet from her daughter. Since then, she has continued the affair with her son-in-law, sneaking around behind her daughter's back. One night, after Mitsuyo's bath, her son-in-law comes to her, and they indulge in pleasure through fellatio and fingering. Later, he also has sex with his wife, who is ovulating. Mitsuyo masturbates with a vegetable while imagining it. She thought these secret days would go on forever, but...