Honestly , I do not recommend this drama to anyone looking for something fun/new to watch. I personally watched it because it had high ratings so I had many expectations from it but I ended up highly disappointed. Prison Playbook was very hard to get into for me. The beginning was extremely stretched out and I was really close to dropping it many times but the characters  were so lovable that I couldn't drop it even though I wanted to.
This drama's strongest point is the relationship between the characters and how it evolved. Seeing the characters bonding was very touching. Unfortunately, that's about it. There are no interesting events happening , no surprises , nothing else to keep the person watching interested. I know for a fact that if I watched this drama while it was still ongoing , I would have dropped it as it's merely a narration of events. The ending was very disappointing for me as there was no closure, just a typical korean drama ending. I still gave it a 6/10 because the acting was just so brilliant and touching that by the end , I felt connected to characters of the show.