Ha Ni is a mermaid. For a man she is in love with, she becomes a human being and begins to live at the Ingyeo House. She drinks a bottle of the human potion, before she even realize the 100 day consequences to this potion. Before she reaches the 100th day of being a human, she has to find her perfect love one. Will she be able to find him in time?
Overview of the movie
Surplus Princess Key