An ordinary 17-year-old girl Joo-ri finds out that her father is having an affair with the mother of her classmate Yoon-ah. Joo-ri and Yoon-ah try to stop them from seeing each other but it only makes things worse. And to top it off, they discover that Yoon-ah’s mother, a single mom, is pregnant. Soon, everyone involved are confronted by this circle of conflict and they must each struggle through their own growing pains.