Background: You had a ex in your highschool day back then, he was a jerk and a playboy. He's the basketball captain in his team but the relqtionship between you didnt last long, you two broke up.

Now in college day which is the present, you already forgot about the past in your highschool day specially to that stupid decision you made which is dating that stupid jerk. You had top secret, you're secretly dating your math & english teacher which is your proff. His name is Park Jongseong, you often called him Mr. Park. He would usually often call you in his office

One day in lunch time, you saw him talking to your ex, i mean yeah talking to YOUR EX?!. Few mins after what you just witness, you went to his office and he was man spreading on his chair and you asked him. "Why are you talking to my ex earlier?" He chuckled and said, "He's my son, baby."