Yesung was the playboy of SM high. But everything changed when he met Krystal, who is a playgirl secretly. They went out with each other for only 6 HOURS!. Krystal stole Yesung's heart in just seconds but Yesung didn't stole hers instead she used him to make the one she loves jealous. When Krystal told the truth about her plan, Yesung's heart broke into pieces, tiny pieces. On the same time, he got the feeling that he gave to the girls that became his toy. He was suddenly scared to be heartbroken, scared to love someone. He was no long the playboy that he was. He made a promise to himself that he would love only one more girl, his true love.

He search for his true love and will end the journey once he found her.

A few months later, he met Yoona in the park. Yoona went to JYP high, the rival of SM high. Even though their school are rivals, that didn't stop them from being friends.

Yesung slowly opens his heart for Yoona. But Yoona never opens hers due to the incident that she went through a year ago.

Will Yesung find his true love?