I watch some shows for the good romance.
I watch some shows for some good action.
I watch some shows for a good mystery, with plot twists.
This show had them all.

The top notch acting makes me surprised I haven't run into these actors on anything else. That includes supporting actors as well, and there were many, with good storylines of their own, and interesting arcs. My wife is not even a kdrama fan, and she was hooked as well.

Go watch this show. Now!