Kimika, a mother who raised her son Ikki single-handedly. She spends her days day in and day out at her job in order for Ikki to go on to higher education. One day, she is forced to get married by Sayama, a man who has been in love with her Kimika for a long time. And, unexpectedly, Ikki witnessed the scene where she gave Sayama her body. Kimika tries sex education to correct the sex of her son who runs away.
