The story revolves around relationship of Do Min - Joon (Soo Hyun Kim), a man who came on earth from outer space 400 years ago and Cheon Song - Yi (Gianna Jun), famous actress with hard character, who resembles a girl who Do Min - Joon met when he came on our planet. They cross their roads by becoming neighbours. Do Min - Joon, who isn't a communicative person, is still dragged into dangerous and comic situations with Cheon Song - Yi, while feeling mystical connection between her and the girl he met 400 years ago. By time, he develops romantic feelings towards her, but is trying to deny it because he does not believe in love. Though, while series develope, he starts protecting her from a man who tries to kill her. He has left only 3 months time on earth and is starting to have doubts about if he really wants to go back or not. He takes advises of his only friend lawyer who he saved 30 years ago. Cheon Song - Yi is in love with a man who saved her twelve years ago but doesn't even remember his face. Ironically, this mysterious man appears to be Do Min - Joon.