This is quite an original thriller with an addictive plot very well directed with amazing actors.
Every episode starts with a flashback that helps to understand the plot and main characters' personnalities and emotions. There is indeed a psychopath but also people with traumas and mental or social disorders... this make the all drama quite interesting.
The main love story is just very touching and emotional and you really don't know how it will end.
Lee Jong Gi is just wow wow wow !
I highly recommand this drama for the stroyline, the actors, the OST and fhe emotions you will go through watching it !