Yuka, a serious and innocent female college student, was troubled by her unsatisfying sex life. Her life takes a dramatic turn when Akikawa, her father's friend who had been her private tutor since childhood, gets drunk and is drawn to her now fully matured body. Initially hesitant, Yuka is soon overwhelmed both mentally and physically by his expert, middle-aged techniques—something she's never felt with her boyfriend. After that day, she transforms into an extremely sensitive woman, her pulse racing at the mere sight of older men.