IU and L.Joe have been friends since they where young. They met when L.Joe started to take dance and singing lessons at IU's parents studio. He is in Love with IU and lets her know it but she only sees him as a no good play boy and a childhood friend. no matter what he does he can't get rid of his playboy image. The truth is he doesn't know how he got it in the first place.

If that wasn't a big enough obsticle to get around there is another one standing in their way. L.Joe has a twin brother! this guy seems perfect in IU's eyes but to everyone else he is the no good trouble maker. Now they are older and they all work together at Studio where they met. Who will IU end up with? Will she see through Soohun's mask or will she continue to think he is the good twin?