A young gril name Yoon Eun Jo. A senior in high school and is going through life by herself. Her friend name Kai has a sercet that only she knows and tries to keep her life simple until she meets Choi Young Jae who also has the same sercet as Kai and both are very popluar from the girls. As she starts to get close to Young Jae, all of a sudden he leaves and returns back 2 years later...but is it the same Choi Young Jae? And what will happen to Eun Jo and Kai's relationship when Young Jae leaves and returns again..