Initially, the drama has a lot of potential. It has a good premise and an interesting plot, but ultimately it suffers from "trying way too hard to be more than just a romance drama", something that I've seen happening before (with Queen: Love and War for an example). This drama has good leads with good chemistry and a very cute love story, but unfortunately the romance gets pushed back for the sake of focusing on the murder mistery, investigative plot. The problem with that is that the story has way too many plotholes and conveniences that happen just for the sake of moving the story forward or creating more conflict, to the point that sometimes I just got irritated. It was still interesting at certain points, but way too predictable and flawed to be considered a good murder mistery.
As I said, the lead couple has a nice love story, but because the writers are trying way too much to focus on the murder cases their romance feels rushed (even though it takes many episodes to actually happen), delivering a mediocre investigative plot and a great, but underdeveloped romance.
The supporting cast is good, I specially loved Hee-Jin's redemption arc and Dong-Cheol was a nice character. As for the leads, Cha Min is very cute, he has basically everything I love in a male lead and even though he's rich he breaks the stereotype of cold, scarred by the past chaebol by being an actual sweetheart and very obvious about his feelings for Se-Yeon from the start, while she's an actual intelligent, strong female lead (even though a little egoistical and petty at times), making me like her instantly since k dramas tend to portray women as dumb or weak.
Overall the drama is ok, I'd recommend it for people who don't have anything better to watch, just don't go with your expectations too high.