This is a good solid drama. Good acting, good story I didn't notice the music so it must have been OK. There's enough suspense and the story was engaging enough to keep from dragging for the entire 16 episodes. Even though the story is about serial killers and is quite heavy, there's enough comedy to stop it becoming too sad or too heavy. I cared about every character, good or bad, by the end, so, great characters and great character development. Seo In Guk was excellent as Lee Hyun, I first saw him in Love Rain, and thought he was quite a good comedic actor, then I saw him in The Kings Face and thought he was quite good as a romantic lead, and now I've seen him in this and I think he's good as a "serious" actor. He really is good. I think after this I'd watch anything he's in. I've never seen Jang Na Ra in anything before, and now I want to go and watch everything she's ever been in. She's great at both comedic and dramatic scenes. I really enjoyed her. Her character was great and she had a lot to work with and did it well. The rest of the cast were great everyone did a good job, there were no hangers on. To the writers: I'm only rating this 7.5 because of the crappy ending. Look, the last episode is not bad enough to ruin the whole drama, it's just lazy and if you're going to do do one of those endings that ties up all the loose ends, don't leave more loose ends (unless you're planning a sequel - please plan a sequel, because then I will take this back and give it an 8.5)