Joon-ki is working as PE teacher at high school. One day while his students are playing dodge ball Yeong-eun catches his eye because of her boldness. After that Yeong-eun openly shows her emotion towards her teacher. Confused Joon-ki tries to keep away from her. But soon he ends up with kissing and touching her charmed by her youth and beauty at school. He feels terrible for his pregnant wife Seo-yeon, and wants to end this strange relationship. But Yeong-eun asks more and more for keeping that day’s secret. A rumor spreads until his wife picks it up. Joon-ki’s wife meets Yeong-eun by chance, and is shocked by Yeong-eun’s pregnant-like behaviors.