40-year-old Hye-Jung (Jang Seo-Hee) is a professor in the Department of Sociology at a university. She prepares a paper on extramarital affairs. One day, 21-year-old Woo-Sang (Jung Suk-Won) appears in front of her. For the first time in a long time she feels like a woman. She wants to love him and is loved by him. Meanwhile, 21-year-old Woo-Sang is an unstable young man. Woo-Sang can’t approach Hye-Jung easily.