I am a huge fan of the Korean historical epics and this one is good but not as good as some of the others I have seen.
If you haven't seen any of the others, don't make this your first. Check out Kingdom of wind, Chumong, warrior Baek dong Su and the tree with deep roots. If you have seen a bunch of them and are looking for more, this is worth the time.
It tells the story of the rise of the most famous king of Baekje. Baekje was one of the three kingdoms of Korea around 2000 years ago. He transformed them from a small state to a serious player as he attempted to subjugate his neighbors and unify his country.
The show takes a long time to get going but once it does, it is enjoyable enough. The casting is a little off in my opinion. The main character is a short fat guy, not what you normally expect for the story's hero.
Not that it is massively important but the attention to detail is a little off too. The soldiers armor has noticeable plastic clips a few thousand years before plastic and injection molding were invented.
Still, this is better than any of the American made historical epics and any criticism is only because the other Korean shows set the bar so high. The American made Show Marco Polo, for example, was a disgrace in comparison to this.
Check it out if you are a fan of this genre. Probably not one with universal appeal IMO.