Hayoon, 20 year old and a repeat student, has always lived by her own rules— alcohol, cigarettes, and boys. But Her world is shaken by the arrival of Hyungwon, a new homeroom teacher. He’s unfazed by her reputation and an unpredictable natured man, sparking a curiosity in Hayoon that soon blossoms into love. Unlike other guys who'd easily fall for her, Hyungwon is a man with an impenetrable emotional barrier. One-day when she confesses her love, he dismissed her confession saying,"it's common for students your age to confuse infatuation with love." But Hayoon isn't one to back down. This isn't just a fleeting crush; it's a war for his heart, and she's determined to break down every single barrier.