I am not sure how I feel exactly about this drama. The best description I can give is "mixed".
It was... okaaaay... on the overall. The overall story and plot were good, but I can't say the same for the script. There were a whole lot of "letting things pass" for me to make it through to the end.
I had initially given up on the first episode - I found the premise of Ma-ru taking the fall for Jae-hee's homicide unbelievably stupid, but when I rationalized it with blind love and devotion, I was able to move past it.
Song Joong-ki as Maru was perfectly cast. What frustrated me though, aside from his being gullible and pathetic when it came to Jae-hee, was that it wasn't clear when his feelings for Eun-gi became real, sincere, and distinctly different from when he first thought of using her for revenge.
Moon Chae-won as Eun-Gi was effective. Nothing great with her acting, but not bad.
But Park Si-yeon was uni-dimensional as Jae-hee. She had only one facet and her monologues were deadpan boring. Super old-style acting. She was reciting her lines rather than acting them.
Couldn't praise the soundtrack either and I had to keep reminding myself that this series was from way back 2012. But still.
Starts strong, but drags starting around episode 12 that I had to skip episodes 15 and 16 and speed-watch episode 17 and still manage to keep up with the story.
Worth watching if you're forgiving of a lot of lapses in logic and some second-rate acting of a pretty face. And if you are extremely patient.