Ko Mi-Nyeo & Ko Mi-Nam (both played by Park Shin-Hye) are twin brother and sisters. They grew up in an orphanage and never knew their parents.
As a young adult, Ko Mi-Nyeo is set to become a nun. On her way to pick up a ticket for Rome a strange man catches up to her. The man's name is Ma Hoon-Lee (Kim In-Kwon) and he explains that he's the manager for popular boy band "A.N.JELL". He also explains that her twin brother Ko Min-Nam, who just joined the band, was seriously injured and sent to America to recover. Ma Hoon-Lee then pleads to Ko Mi-Nyeo to impersonate her brother until he recovers. For her brother's sake, Ko Mi-Nyeo reluctantly agrees to play her brother.
A.N.JELL band member Kang Shin-Woo (Jeong Yong-Hwa) first discovers Ko Mi-Nyeo's secret, but he keeps it to himself. Kang Shin-Woo also tries to help her out without Ko Mi-Nyeo knowing. He also starts to develop feelings for her.
Meanwhile, A.N.JELL's singer/songwriter/vocalist Hwang Tae-Kyeong (Jang Keun-Suk) discovers Ko Mi-Nyeo's secret. Hwang Tae-Kyeong is an extremely gifted musician, but his personality is cold and he is a control freak. At first Hwang Tae-Kyeong tries to kick Ko Mi-Nyeo out of the band, but he becomes sympathetic to her plight when he discovers that she hoped to find her mother by appearing on television with the band.
Ko Mi-Nyeo's secret is then discovered by pop singer Yu Hee-Yi (Uee) by chance. When the media falsely reports that Yu Hee-Yi and A.N.JELL band member Hwang Tae-Kyeong are dating she uses Ko Mi-Nyeo's secret to make Hwang Tae-Kyeong pretend they are dating in front of the press. At the right moment Yu Hee-Yi will announce to the press that they have broken up and that she dumped Hwang Tae-Kyeong. In return Yu Hee-Yi will keep Ko Mi-Nyeo's secret. Hwang Tae-Kyeong agrees to this arrangement to protect Ko Mi-Nyeo. Meanwhile Yu Hee-Yi starts to develops feelings for Hwang Tae-Kyeong.
