Go Mi Nyu is a sister-in-training. When her twin brother Go Mi Nam successfully auditions into the musical band A.N.JELL but is forced to leave for the United States to correct a botched plastic surgery effort, she is approached by his manager to pose as Mi Nam for the duration of his recovery. Against her wishes, Mi Nyu accepts in order to fulfill her brother’s dream of finding their mother. Now, posing as Mi Nam, Mi Nyu enters the group A.N.JELL and meets its members; Hwang Tae Kyung, Kang Shin Woo and Jeremy.
Initially disliked by Tae Kyung, the group’s leader and composer, Mi Nyu slowly falls in love with him, only to find herself entangled in a love triangle between him and Shin Woo. Jeremy also harbors a one-sided love for her despite not knowing she’s a girl. As a result, all three members of A.N.JELL fall in love with Mi Nyu. Additionally, Mi Nyu finds herself rivaled against Yoo He Yi, an actress who also has feelings for Tae Kyung.
Now Mi Nyu has to wait in the “Mi Nam disguise” until he comes back from US, but its not easy due the media and paparazzi. Will she be able to hide her identity? Will she be able to keep up with this little secret that she is not a guy until the real Go Mi Nam comes back..?