Park Chaemin is a secret agent from the best agency. She have completed a lot of missions successfully. She looks cold but actually have a kind personality. She always put others safety before hers, especially her friends and family. Chaemin will become Blackpink's 5th member. Being a K-pop idol has always been her dream. However, there is someone trying to kill BTS and Blackpink. What happens when she is send to protect BTS and Blackpink, the famous K-pop group?