I was luke-warm about this show based on its description:
A prickly, sensitive, and hot-tempered queen, tries to turn her trouble-making princes into proper candidates to be the next Crown Prince. But wait, isn't the firstborn automatically the Crown Prince? Well yes, but there are complications.
There are a LOT of characters. (Pro-tip: create a link to this webpage on your phone while you watch
Starts a little slow, but builds toward the mid-way point! This show is airing on weekends in Korea, and the viewing numbers keep increasing.
But getting one of her sons picked to be the next Crown Prince, is only half the battle for her. Then there is the question of his wife.
All of the problems she has is caused by a really great villain!
I thought that toward the end, some things happened a little too conveniently. But perhaps I was not paying close enough attention. You do need that AsianWiki page handly to keep track of the relationships.