I don't have time to go into details, but also I cannot give spoilers anyhow. I can give this drama the best endorsement I am capable of as a person who has seen A LOT of Kdramas: I have completed 244 dramas (nearly all Korean, a couple Chinese). I had but 1 that I rated a 10 - Signal....until I finished this one. I now have two dramas ranked 10. Yes, it's that good. There are no flaws. This drama is as good as Kdramas get: writing, directing, acting are all superb. There is never a facepalm moment. The lead male is perfection. The lead female is also, for a rare change, perfection! A truly competent and not in the least annoying female lead in a Kdrama, what a rare thing indeed! I had high expectations for this drama given the lead actors. I was not disappointed!