Season 1

Kang Joonsang moves to a new high school in search of his biological father. Jeong Yoojin and Kim Sanghyeok are close childhood friends, although Sanghyeok wants to be more than a friend, Yoojin sees him as a brother. On a trip together with other high school mates, Oh Chaerin, Gong Jinsook and Kwon Yonggook, Yoojin is saved after an accident by Joonsang. They become close and she opens up his cold heart. However, circumstances and fate dictate that their love will never be. He abruptly disappears from their lives. Ten years later, the old High School buddies gather to celebrate Yoojin and Sanghyeok's soon-to-be wedding. Yoojin, who was deeply in love with Joonsang, still has a fire in her heart for him. But at the party, Oh Chaerin's new boyfriend arrives, who appears the same as Joonsang.