ONE thing I can say about this drama is that it is NOT a RELAXING drama, but a PAINFUL, STRESSING drama. You can't find any laughter or positive scenes in this drama, but you can witness how evil people can go, even if you are close to them.

HOWEVER, considering the plot and the setting, this drama was not that bad like others are criticizing.
I think the ending was well done, despite all the negative and betraying story line until episode 31. Until the end, this drama was full of sad, gruesome, irritating, and questioning scenes. I was really curious how the "motive", the three had in the beginning for Tae Hee, will cause issues, but over all, it was well scripted.
Story: I think it was based on a novel, but the directors did a great job turning into a screenplay. Not only the plot but the choreography and the shooting places were great too.
Acting/Cast: The casting choice had no problem. One thing I want to say is that they lack a bit of facial expression. Everyone had almost only one or two faces that they were really difficult to read their feelings sometimes. Some are criticizing Joy's acting, but I think she did a great job.
Music: I really liked the intense OST they had with violins.
Rewatch Value: If you watched once, I think you may rewatch it if you want to see the cute couple again.

Overall, this drama was well made, and I really enjoyed it. At some point, I was questioning how low everyone will go, since even some promising characters betrayed the viewers. I really loved the way the drama was rapped up, cause it was not something unreal, but logical and reasonable. To be honest, I was also okay if the drama was ended in a completely negative way...