I think it is the right tagline for this drama. When you think you got the culprit, it was not the end.

This drama is well written, although it involves story of two different world, the transition is clear and not confusing. What i like from kdrama nowadays is no character appearance being wasted. Everything is connected.

It was predictable at some point, but behind the predictable one is another unpredictable plot. That's why i said, when you think it's over, it is actually not. Like other drama, if you think they got the culprit at episode 9/12, there must be somehing unsolved over there.