Han Hyo Joo as always amazing, her chemistry with Ju Ji Hoon was so good, but yeah no romance drama so do not expect any confessions or kisses - although I wish there was. Moving to the plot, it was really interesting.
There could be easily second season, there is an open ending and the one which creates more questions than answers, like I really need to understand what exactly happened and how that will work. So as far as open endings do not bother me, I like them sometimes, this one needs more explanations.