In both dramas parents are trying to save their daughters. Both are suspense thrillers with lots of action.

Both leads are desperately trying to save their loved ones. Also, both are filled with suspense and mystery.

Both dramas deal with secret organizations, the action scenes are amazing and the leads will stop at nothing until they accomplish whatever they need to.

In both dramas the leads go on a journey to save their loved ones. Also, both are filled with action and mystery.

In both dramas the leads unveil many mysteries involving people close to them and most characters seem suspicious except for the leads, story is filled with drama and suspense. The vibe is pretty similar.

Secret Door's King Yeong Jo and Cruel Palace - War Of Flowers' King Injo share a lot of similarities emotionally and in portrayal of characters. Both kings are portrayed very human and with lots of emotions, fears and scars and fragility. Both kings were enthroned by a coup. Also their relationships with their sons are very similar too, with very conservative fathers and less conservative sons. Also, I'd like to say Cruel Palace's Crown Princess is almost like a female version of Secret Door's Crown Prince Sado. Both dramas are very political and I feel that if you liked one you will like the other.

Both dramas deal with matters of royal and imperial harems. But the story in Cruel Palace isn't limited to the harem itself as in Legend Of Concubine Zhen Huan/Empresses In The Palace. Cruel Palace deals a lot more with politics. If you want a drama that deals with the harem but it is not entirely about that, maybe you should give a try to Cruel Palace.

Same setting, same characters. Both are about the Manchu invasions of Joseon. But unlike Three Musketeers, Cruel Palace is not an action drama, instead, it focuses more on the drama.

Both dramas are highly political, both have leads who dream of a fairer world and besides, Han Seok Gyu plays amazing kings in both (I never thought I could see him in another king role because I thought it would never be as good as Se Jong, but guess what he's just as good as Young Jo or even better.) Both are equal in quality of story and development of characters and both dramas deal with factions that oppose each other. I just feel that if you liked one, you will like the other.