This may be a long review, but I wanted to point out a few things how I felt about this drama compared to what some others have written.

I love this show, in a way, I'm like GT, but I'm slowly working on healing. Exactly how this show does with the characters, they heal over time. Some people think that the beginning of the show was the best and then it slowly deteriorates from after the first 5 episodes. This show starts as a dark/gothic/mystery. But the only reason that is, is to set the stage for when the healing begins. Healing is a slow process it takes time. Like the way this show does with the characters.
The comments that I've read that kinda peeves me a little. Is that some think that it's the 'my mom killed your mom' cliché. It's not a cliché for how they did this. They did it with style and a way that makes sense and moves along with the story.

Now the biggest problem ALOT of people seem to have is the mother arc. Why is her mom still alive and why is it the Head Nurse. The Head Nurse was least likely person (at least to me). It also didn't need to be a random person we've never met. That would be harder explanation to buy. But the mother needed to be alive for our main characters to heal. There wouldn't have been any closure if she wasn't alive. Also with the mother arc comes with, how did she survive. And this part I may get some backlash for but: I'm okay with how they didn't explain how she survived. Not gonna lie, at first I was a little disappointed that we didn't find out how she survived, but then I got to thinking about it afterwards. The first couple of episodes, MY said she registered her moms death years ago. Maybe part of her knew there was a possiblity of her mother still being alive. Also MY mentioned that her mother dissappeared in the basement (we assumed her father collected the body, maybe thats not the case).
Also, what really made me okay with not knowing how the mother died is this: this show has tied up most if not all the loose ends. It came around in full circle, even bringing back patients that have now healed. You think the creators didn't think about this "plot hole"? I think they made it intentional because to really make our main characters heal is to have the mother alive. To confront the past of how GT and ST mother died. And also have MY face her biggest fear, her mother. Also, it doesn't matter how she survived. It doesn't go along with the story. Also, MY didn't care how she survived only now that she was back in her life. She could have easily asked what happened when she visited her mom in jail. But she didn't ask, because she didn't care. It's the same as how it was with her dad. To her both of her parents died years ago. All she wants to do is forget. And thats what she even told her mother, that she wants to forget her.
So to be honest I'm okay with not knowing how the mother survived, because it doesn't matter how, it's that she did.

The reason why I love this show is because it takes you on a journey. A journey you don't expect, but a journey you would miss if you didn't take it.