Based on Hans Christian Andersen's The Little Mermaid. A modern fairytale fiction starring Girls' Generation's Seohyun as the prettiest and the youngest daughter of a rich family. Seohyun spent her life living in a Castle at a secluded island with her eight lovely older sisters and some servants. She is a cheerful and an adventurous girl. Eventhough it is strictly forbidden to leave the castle, it didn't stop the maiden to explore with her only bestfriend, Kyungsoo. Despite of having eight do