Aera Kim has spent four years getting her business degree in the United States, but now it's time to return to South Korea to join the family business: K-Pop music. Her father is the CEO of an entertainment company that manages one of the biggest K-Pop groups in the world, the boy band KOSMIC. But she has a secret, the reason she left for the U.S. and didn't return for four years: she got involved with a male trainee, and someone found out about it.

Hajun Yun is one of the members of the world-famous K-Pop group KOSMIC. He loves making music and being an idol, but he's got a secret. He can't forget this girl he met as a trainee, who vanished without a trace one day. And when she reappears years later, he realizes he'd still do anything to get her back in his arms. Even if it means risking his career and everything he's worked for his entire life.