Alcohol, cigarettes, men. Ha-yoon, a 20-year-old repeat student, lived surrounded by all the wrong habits… Until her homeroom teacher Hyung-won suddenly appeared in her life! Unbothered by the rumors people whisper behind her back and always defying expectations, Hyung-won piqued Ha-yoon’s curiosity. And for the first time, she came to understand the feeling called love. “I like you, Teacher.” “That’s not love. People your age often confuse it.” But unlike the men who always gave in with just a little push, he’s the most unshakable man in the world, and it won’t be easy... Still, that’s fine, because I’ll break through that iron wall no matter what!