This story was unique, it didn't waste too much time, and was rather enjoyable. This drama's genre didn't appeal to my psychographic which enjoys (mostly) fantasy-comedies, but this Drama was so undeniably good that I had to leave a good rating.
Lee Joon Gi was already an actor with enough star-power for me to try to follow each of his projects, but now methinks I found/was reminded of some more actresses that I'd be interested in seeing what they do next [See: Moon Chae Won & Jang Hee Jin].

Aside - The end of episode 11 really sold this show for me. That moment was a 10/10 for me.
P.S. Flower of Evil is a show that's apodictically very goods!