A young man, overwhelmed by desire, finally decides to book an appointment at a soapland, hoping that going with a new, inexperienced girl might ease the embarrassment of still being a virgin. But to his shock, the woman who appears is his own mother, Shizuka. Confusion and disbelief flood his mind. Calmly, Shizuka introduces herself as "Mizuna, a new girl," and begins giving him an intense, intimate service. His long-awaited first sexual experience ends in emotional turmoil. The next day, when the young man confronts Shizuka, an unexpected turn of events awaits.