To answer: No, it's just that nothing happened.
I was very excited about this drama and, as I liked Jang Ki Yong, I hoped I won't mind the existence of Song Hye Kyo as a main character, since after watching her act in a drama made me avoid every single one that she ever acted on again. To be honest, I'll have to admit that JKY isn't any better in acting (he acts the same as a cheating boyfriend, son of a murderer, killer etc) but somehow his charisma makes it more bearable.
This being said, you can imagine what happens if you pair them: you try to cover a disappointing storyline with good looks. For some viewers that is enough but I'm sorry that not for me.
For only 2 episodes a week, you'd say you can watch them and not get bored but, after really trying, I couldn't. I stopped mid episode to write this review (I'm curios in a few months, when people will have access to all the episodes, if the percentage of people that dropped it will increase)
Nothing really happens, there is no central conflict (for real, I mean. They tried to come up with one but it is and isn't there), it feels like they're dragging the episodes so they can reach the end. Also, you can figure out the plot by yourself after watching 2 episodes.
One last thing that I want to say is that the "one night stand" kind of a situation is overly used to cover up a bad drama and it's beggining to be a clichee (the new post accident amnesia)
Life is short guys, watch a good drama.