It was totally fine up until episode 8. By ep9 both acting and writing got super awkward, events started not making things and are only happening to advance the plot, relationships became artificial and dull, and there was a noticeable overall drop in quality. One thing that really bothered me is how everyone was heavily reliant on the key chain. This plot element was handled poorly from all parties involved. Also, police force was comically bad how they handled the case. No follow up on Se Ra and Joon Ha they were no where to be seen after their last abrupt conversation, I guess the writer forgot.