You as Choi Hae Yoon is a normal 17 years old high schooler. A nerd and don’t have friend at school. But, you are a young model for a fashion magazine.  Also a daughter of your parents who is a famous actor and actress. Had a brother, Yo Seob and a childhood friend, Doo Joon. Altought you is rich, but you works at Moshi Cafe. A week before your birthday, your parents died in a plane crash accident. Your parents give you a will. One of it was a yellow rat (?). There was a secret about it.. Then, someone came in your life. You really hates him because he is annoying. Who is the man and what's the secret about the yellow rat?