After moving to a rural location with lots of nature for her son, Mariko has striven to be the best mother she can be. She is spending her housewife days bored beyond belief when, one day, she meets her son's friend Keisuke for the first time in a while... and becomes enthralled by the stimulating sex she has with him. They secretly have sex while her hubby, son, and her son's friends are all nearby under the same roof. Conflicted by the divergence of her actions from her ideal image of the perfect mother, Mariko attempts to return to her boring old lifestyle, but...