Nakahira is a university student who works part-time at a convenience store. Despite not doing well in studies, he excels in his part-time job and is promoted to train new employees. Sayama used to be a teacher but had to give up her dream and become a full-time housewife due to her husband's busy schedule and lack of attention. Sayama decides to work part-time to pass the time and earn extra income. As a newcomer, Nakahira helps her a lot, and they become closer. Nakahira shares his academic struggles with Sayama, who offers to use her teaching skills to help him. When they return to Nakahira's place, the air conditioner is broken, and Sayama's sweat soaks through her shirt, prompting her to take off her jacket. Sayama's sensual body captivates Nakahira's gaze, and noticing his interest, Sayama decides to teach him about 'sex' to help him focus on his studies more...