How can a mermaid from the Joseon era survive in modern-day Seoul?
Jin-wook asks her the reason why she left him and she replies that it was just a one-night stand. She is very energetic and receives recognition for her work, but her only interest is in CEO Eun Hwan-Ki. So-Rim has fallen in love with Han-Gyul at first sight and has made up her mind to find him and confess to him.
For So-Rim, her life changes completely after meeting with Han-Gyul, her voice gets her into a music industry with her two childhood friends and forms a band called Mush&Co.