Lee Hae Eun is a simple, smart, and shy girl who will never expect that she have a famous, handsome, and talented cousin, Park Chanyeol. He's an almost perfect guy who could sing, rap, act, play music, and everything else. But she'll also never expect that he has 11 friends who are just as cool as him... Then, how will her life turn to be? Will she going to be just fine... or will their presence affect her? And will she let herself fall in love for the first time?