I love how they start and end this drama with an interesting riddle that will hook their viewers to think what really happened from the past, why did he give that riddle and what does it mean. This drama will also makes you think how and why did he made that tragic incident. Also, one of the interesting part is how the writer made it an unusual kind of crime investigation because of a mutant kind of characters, though not all of them has an extraordinary kind of intellectual and physical powers. I hope that there's a season 2 for this drama.

I like the casting and acting of everyone except on hyewon. She's facial expression for all of the emotions are the same. As for Nam Goog Min, as expected he owns the character of this drama. He never disappoints me in his acting from 1-16. I also like how he change his tone of speaking for his character here.

Music: I love the music! I'll give 100% score for the composers of the 3 ost. The music will make you feel the thrill and the mystery, the sadness and the curiosity. I personally love Set Me Free night ver of Ha Do Kyun. He sing the song with full of emotions. He delivers the meaning of the song perfectly even the one who cant understand korean can feel the sadness, the frustration, the desperation and the determination of his song. The lyricist really made a great lyrics for this drama.

I will definitely watch this drama again.