I really liked the story for Tree with Deep Roots. It is about the King of Joseon (Korea) who invented their alphabet as a simple way for his people to learn to read. Before that, they used the Chinese writing system so only the noble class could learn as there are thousands of letters and poor people never had the time. I have no idea if any of it is based on a true story...
The focus is that there are numerous groups who are trying to stop the king publishing the new letters and they will go to any length to achieve their goals. Hidden Root is a secret organization who make stopping the new letters their priority and the king has to defeat them to succeed in publishing his new writing system.
The star of the show is a slave whose parents were killed by the king when he was a small boy and he starts off trying to get his revenge by killing the king until he learns about the project to help the people.
It's slow to get going. You need to watch 4 episodes to get into it but after that, it's got plenty of action including great martial arts / fight scenes. It's only 24 episodes in total which is short compared to some of the other Korean historical dramas but it feels about right.
I recommend this for fans of historical dramas and Martians arts etc. I doubt there is much universal appeal here. If you don't like historical stuff and have no patience for subtitles, this isn't the show to change your mind (probably).
I watched it on drama fever and the translation is very poor. There are loads of obvious mistakes that stop their sentences from making sense on occasion. I wish they would improve their quality control or get a native English speaker to go through it before releasing it.
