Takashi has a loving girlfriend, but when it comes time to do the dirty deed, he finds himself unable to perform. On a train ride following this incident, Takashi discovers his teacher, Misaki, getting touched by a subway groper. Strangely though, instead of getting upset, Misaki seems to be enjoying it. And much to his own surprise, Takashi does too. Thus begins Takashi's journey as a pupil to his teacher in a most carnal sense when they meet on the train every morning. As he explores his desires with his teacher, Takashi becomes a more confident lover. But will his new knowledge help Takashi become closer to his beloved girlfriend? Or scare her away?