First - The Main 5 Characters of this drama are really very good , They showed their Comic skills with Detective skills which I think is Very good.
Second - The story of Each character also has deep meaning which can add some emotions to the story.
Third - The Friendship between them was deep and as well as it was fun to watch
Fourth - The Victims also had their roles and special characters which gave good story
Fifth - I don't know whether I can say I had expected that the friend of the Hero is only the culprit but I dropped my Idea in midway but unexpectedly it became true .
Overall , I really liked the drama and it was really fun as the five of them explore everything and specially I liked every Undercover Operation . they were really hilarious.
I don't If it is Underrated but I really suggest to watch this to laugh and watch something light hearted with great story and acting.