This is actually the first time I write a review although I thought that I would never do it, but after watching this movie I couldn't help it.
The story was really well written, starting with this character that will frustate you, why? because he is the purest and kind person and you will adore him,  yet he becomes falsely accused and you'll become enraged by all the injustice that happens in the world. The way he treats is daughter makes you feel warm inside, in spite of his disability he is the best parent she could have.
As I said the relationship father-daughter will move your feelings but also the friendship of the 7º cell mates, those who will do everything in their power to help him.
The acting was on point. I already new that those actors were great but I really got impressed by Kal So Won acting, for such a young child taking such an emotional role she was amazing, every time she cried she shattered my heart into pieces.
The soundtrack was really good but in some parts I was so immersed on the story that only after some time I would notice it, like if the music was blended in the story.
I had this movie on my plan to watch for a long time and I regret that I haven't seen it sooner.
I don't recall crying so much after seeing a movie or drama, it was like a storm of emotions inside of me and even 5 minutes after the movie I was still crying, so be prepared with a lot of tissues.

It is simultaneously the most beautiful, loving and sad story that I ever seen.