I admit that the first few episodes of this drama got me hooked up, with all the murder mystery and puzzling psychological issues of the main leads. but gradually the story lost its initial suspense and turns into your everyday boring love story. The reason for this is,
1. the murder mystery at the beginning that made me hooked up, turns out to have nothing to do with the main leads and has everything to do with the second lead.
2. the weak plotlines to connect the main leads to the murder mystery and a nonsensical backstory to back up the current plot. for example, a heart transplant leads the psychiatrist to pursue the murder of his donor. ( let's say this is a valid argument ) but then to not lead this to an obvious tragic ending, the writer adds a sprinkle of some supernatural stuff to make the viewers not feel too devastated about the "going to be a tragic ending". And the female lead who happenstance to cross paths with the murder doesn't seem to be quite solid to put her in the middle of the whole mystery.
3. adding a chaebol family and many other weak characters to patch up the already disastrous plot holes.

The only good thing about it is the first OST, which is a killer song. which I'm currently listening to on repeat.
The acting is good, the supporting actors are also much more fun. The light friendship, I have to say, is quite fun to watch.
Let's just say that my initial excitement for this drama, gradually ended up with disappointment.

P.S - am I the only one who crack open my skull trying to figure out which twin is which??!!