The story of relationship between X and Q, high-school students. X has fallen in love with Q at his first – school day. He tried to win Q’s heart in a short period of time because he had to participate school activities and after that, he would graduate and leave the school. It meant that he had a less month left for this mission, therefore, he chose to apply the 21 Days Theory.

X brought himself to stay surrounding to Q as well as turned Q on him. He took several tactics to approach and hit on Q, for instance; friendship intimacy, competitive arousal theory, affection from elderly in family, until Q gradually liked X without self-recognition.

However, their relationship didn’t go smoothly. Due to Q’s hot-tempered, it caused to separate Q and X for a long time. However, they kept patient and eagerly waited for meeting each other again. Finally, they opened up the relationship and learned about each other.