If your planning to binge-watch this drama then good luck!! cuz calling this drama intense is an understatement. You are most likely going to get a stroke watching it. The story is very detailed with multiple things happening in one-time frame so at times it's even overwhelming to keep up with how fast this drama spans out. This drama basically is about uncovering the mentality of a psychopath, the topic is deep, and if your too empathetic you're most likely to end up feeling like a psychopath yourself at the end of the drama.
The drama focuses mainly on the mystery and chasing after a psychopath, so there is no romance to talk about. although at one point they give us a taste of romance it's taken away unceremoniously before we can even enjoy it.
And a friendly piece of advice, while watching this don't try to guess who the psychopath is from the beginning, because whoever you think it is is probably not the one, and even if you do, the story is not gonna unfold the way you think it will. This is one of those dramas where you can't predict what's going to happen next because each and every plot twist is more creative than the one before.
The acting, production, and quality of the drama are top-notch.