Reiko Shimura is a 38-year-old housewife, married with three sons. One day, as she stepped out of the shower, she found her son masturbating while holding her underwear. Initially shocked, the mother gradually gives in to her own pent-up desires, taking her son's penis into her mouth and soaking it with her saliva. Overwhelmed by the sensation, the son seeks her again the next day. Unable to resist any longer, she eventually gives in...