I really liked this. I did. The time travel shenanigans complicate things and the story feels like they change it halfway through whenever the killer is revealed you look back... what is the killers connection with the killers? WHY did this killer go and kill Soon Ae in 2021?! I just have zero clue. Mi Sook doesn't actually play a role in this when the first half she was the major player and the directing from locking on her dirty shoes to her looks to her family life to that brief flash forward into 2021 when they were already back in 1987. 

But overall I liked this. Obviously by the ratings but it is dampened overall.