A mother-of-a-child Arasa-keiko, who leads a life with absolutely no time for herself due to childcare and work. In the midst of her repetitive daily routine, she falls in love with a married man who works at the same workplace. The more she thinks it's wrong, the more her feelings flare up, and the two end up having an affair. They are deeply immersed in the pleasure of doing something bad. However, she resolves to make this the last time.
