通勤電車で痴●に遭遇してしまった数学教師のりょう。同僚の夫と教育論を語る真面目な日常のはずが…不覚にも満員電車の狭い空間で初めて知る、本物の快楽に身体は抵抗できず…。いつしかりょうが持っていた理性の数式はドロドロに蕩け、夫のすぐ隣で声を殺して潮を吹き散らすほどの淫乱教師へ変貌していく。密かに求めていた肉欲を満たす日々を心待ちにする彼女は、禁断の車内調教を求めながら、今日も激しく揺れる通勤電車に乗り込んで…。

Ryou, a math teacher, encounters a pervert on her commuter train. Her normal life involves serious discussions about education with her colleague husband, but in the cramped space of the crowded train, she unexpectedly experiences true pleasure for the first time, and her body cannot resist. Before long, the formula of reason that Ryou had held onto melts away, and she transforms into a lustful teacher who can climax while stifling her cries right next to her husband. Looking forward to days when she can satisfy the carnal desires she secretly craves, she boards the violently shaking commuter train again today, yearning for forbidden training on the train…