Shim _____ is a 18 year old girl who is living an average life apart from her parents but known for being a honor student in a prestigious school in Seoul. Here she meets Lee Hyun, who is secretly Super Junior Eunhyuk's sister and the owner of Donghae's heart, until fate brings Shim _____ falling for Donghae. What will happen? Will she recieve the same feelings from him or be stuck from the love of her ex-boyfriend?