Normally im not the type to write a review but this drama is too good. Let get to the point Story: if u looking for the fantasy drama this one is the must watch. the story is well written. Not bored at all and every episode ending made u curious what will happen in the next episodes and unpredictable story-line. Acting/Cast : No one can portray as choen song yi other than Jun Ji Hyun she can make u smile everytime u see her. She can act in every way, emotion, action,and clumsy :P. Kim Soo Hyun portray a perfect role of Alien with a dont-care-whatever-happen character. As well as Shin Sung Rok as a perfect villain role Jae Kyung. A role that made u scare every-time u see him :). Well i can say no one can replace anyone the role been perfectly chosen. Music: well the music is my ringtone now :P The music fit the story and situation perfectly.... Rewatch Value: For me after the drama end i start rewatched immediately and it still interest me even i know what will going to happen so it 10/10 Overall.. This drama is the best Outstanding,Masterpiece of all drama i have watched. The unpredictable story-line, Acting, and Music made this drama 10/10 :)