My first Korean historical drama series, so maybe I need to give it more of a pass as I understand K-Dramas are marked by a lot of schmaltzy romance, yearning, fighting, and melodrama, quite different than American or European period stories.
My take: Story has a fascinating premise of unasked-for gender role swapping, but this requires suspended disbelief because the Crown Prince is not convincing as a male. It would have been far more compelling to choose a taller, more androgynous actress rather than Park Eun-Bin. Again this would have created a more interesting twist to the "unnatural" attraction that her royal tutor Jung felt towards his Crown Prince/King.
The series is set with gorgeous costuming and beautiful locations that romanticize the Joseon nobility and royalty during that reign. And the lead characters are flawlessly beautiful. For the most part the cast is good, however I wish the script had had less schtick and heavy handed "overacted" attempts at comedic relief. Perhaps slapstick is a staple of Korean series.
Nonetheless, the story itself is full of political intrigue, backstabbing, misunderstandings, sword fights, rescues and deaths. The pace plods at times, with repetitive scenes and far too many close ups on clenched fists, I stayed to see what would happen to Dam-I who was thrust into a role that he/she never had a choice in.
The story would have been more powerful as a political drama with a romantic sidebar, rather than the treacly romance dominating. It was worsened by a cheesy music score, and a closing montage of each episode that was cringeworthy.