After 7 episodes:
The major theme--the children of terribly ambitious parents who grow up trying to please these selfish parents but realize how damaging it has been to their lives. In the end, the two main leads try to fix their wrongs into rights so they can be happy with each other. It's a wonderfully romantic story that is set in a thriller/mystery/political corruption drama that really keeps you glued to the story. I love that the main leads are able to express their love for each other in an adult manner. There is no stupid, juvenile embarrassment when expressing affection. It is real, and the actors do a superb job expressing the characters love for each other. I don't know what will happen next, and that is a BIG part of the appeal. The suspense is huge!

After 4 episodes:
I just wanted to post quickly and say that THIS Kdrama is good!! It's got the best hook that grabs you and won't let go. Mystery romance with maybe a psychological thriller twist that makes you want to keep watching to see what happens next. Great acting by the cast. They are supremely evil, mysterious, timid, intense, comedic, and all sorts of divinely abnormal. The mothers are vicious. They all roll together to take you on the ride of your Kdrama life. We need to get a poll/wager going on who the real 406 is.