" Catch the ghost " was an okay drama.
What I didn't like was some characters and the romance spin on the story. What I liked was the case, the action scenes and the way they wrapped everything together.
First of all, the main case was interesting. They managed to link everything together and, in the end, the final result was satisfying. The villain had background and it was nice that they didn't make it easy to figure out who the ghost was. The action scenes were pretty well managed too. However, the drama was interesting only at the begining and towards the ending. Thus, the main part was boring at times and didn't provide anything fresh.
Then there were the characters. Though I liked the male lead, who was overall a sweetheart, the female lead was annoying at times. It was clear and understandable that she did what she did to find her sister and solve her case, but she tended to ignore or forget her team and act on her own. The leader of the police team was extra unlikable as well. She was bullying the female lead for childish reasons and she acted unprofessionally and idiotic.
Finally, the romance was just not necessary. Or, at least, it didn't work for me. The love triangle was even worse, as it was hardly there in the first place.
That said, the performances were really good, from everyone in the cast, but especially the leading lady who was amazing as the sister and the subway cop.
So, overall, six out of ten.