Unable to bear his son's repeated failures in the university entrance exams, the father asks his friend's wife, Kasumi, who was an outstanding student, to be his tutor. Kasumi gladly accepts and teaches him diligently, but as the lesson heats up, the boy finds the stimulation of Kasumi's breasts pressed against him and her cleavage peeking out from under her shirt too much. The boy can no longer stand the repeated lewd temptations that unconsciously occur...