A nice series until episode 15.
The plot is classical, with two characters fated to one-another by their encounter as young kids, but it's entertaining enough to keep watching. The costumes and settings are a pleasure to the eyes, the music is nice and the acting is great.

However, it feels like only the existential crisis of the crown prince is what makes the plot worth it.
The amnesia of the crown prince has him to mull things over what's happening to him, which makes his character development very deep and interesting.

The underlying theme of the clash between the social classes is would have been very relevant but not that much exploited. The crown prince only mentions it slightly when he has regained his memory back and misses his life as a peasant ( once while he sees the amount of food he is served, and once when he says he still is Won Deuk )

Hong shim is probably the worst character. She stands as a strong and independent woman, yet does nothing apart from yelling at poor Won Deuk. The more the story goes, the more useless she becomes.

No need to add that relationship between her and the crown prince is dull, and their falling in love is unfounded. The story tries to make us think that they went beyond fate ( the proposal as children ) and fell in love for who they truly are, but they actually have no other reason than that for loving one another. Won Deuk proves that he actually is not useless, can read, is smart and quick-witted, but she does not show anything worth being loved.

As for the side characters, they are useless and annoying. While their jokes are probably made to lighten the atmosphere, it is never relevant nor appropriate to the situation.

There are also a lot paradoxical elements in the plot itself.

At the beginning, Hong Shim agrees with her father that they should lie to the amnesic crown prince, making him think that he actually is Won Deuk. However the next episode, she acts as if she was duped by her father that he is that Won Deuk ( and a few episodes later yells at him for manipulating the poor young man )

We can also quote the problem with the man who is appointed magistrate in the village, as he has this condition making him unable to recognize faces, yet still recognizes her even if she is dressed as a peasant, but does not recognize the voice or the attitude of the crown prince.

And those are only a few points why the plot seems rushed and focused on the love story, which could have been put aside for more coherence. The plot is full of such incoherence .

That being said, the series was still enjoyable mainly thanks to the character of the crown prince... until the point of no return, which takes place at the episode 15. Every character meets when they couldn't or shouldn't, the brother's death is too quick and not at the right time, everything seems rushed to end the series as soon as possible and untangle the sub plots.
On the whole, when an interesting theme pops up, never is it taken account for the sake of the love stories... that are not that passionate in the end.