Mother-in-law's pain

Rino marries Shuji, with whom she is physically compatible. Her husband had a stepchild, Hiroshi, but they had a sweet sex life without worrying about it. One day, when Rino hears that her husband is being laid off, she entrusts her body to her boss, Sada, for the sake of her husband. However, due to a work matter, she has no sex with her husband, and Rino's crotch is aching. At that time, Rino finds underwear in Koji's room that she should have thrown away... Rino becomes lustful as she imagines her own body and thinks of her son who becomes lustful. Finally, she seduces her son with her sexy appearance...