Be careful, if u watched signal, your expectation for other k-dramas will be higher! This is really a masterpiece, everything is so detailed, not boring at all, very emotional and full of suspense.. it requires your brain to keep thinking while watching it.. definitely a very very very well written drama, the cast, the writer and director deserve Oscar for this! Everything is just perfect. Ugh.. i am ashamed that i have rated other k-drama with high points, but when i watch this drama, it just surpassed all my imagination. I Couldn't believe that a TV series could this damn good that i need to edit all my ratings for other k-dramas (i was too generous for ratings), now i have edited all other k-drama ratings after i watched this one coz this one is definitely an 11 out of 10! i highly recommend this drama, of course, but again, be careful , the feeling while watching other drama will not be the same again. From the beginning, the story is already strong, my emotion is like mixed together. I feel really sad without being manipulated, true from the bottom of my heart. When i feel angry, i also feel so angry, i cannot control my emotion when i watch this, there is no break at all, everything is so tense until my brain want to explode. My heart pain when i watch the story about detective park's brother. This is really a beautiful drama. :,)