I am merely repeating what was already said by other reviwers: this is a dark story of falling out of love.
It was so dark and hearbreaking that from episode 70 or so onwards I could not stop from crying.
It is also beautifyully acted and produced.
2018 was definitely a superb year for Chinese cinematography, if we consider only this title, "The story of Yanxi Palace" and the "The story of Ming Lan".
It was interesting to watch how the same historical figures (Emperor Qianlong & Co) and the same palace scheming became the pretext, the backdrop for two very different stories.
And I do not mean that on the superficial level only, that is the good girl and the bad girl switching places in the "Ruyi's Royal Love in the Palace" versus "The Story of Yanxi Palace".
I mean that "Ruyi's ..." is dark all around, taking you deeper and deeper into a despondent state, as despondent as the one the main female character was in.
While "Yanxi Palace" makes light of life's hardships, providing you with a sense of vindication each time the main female character (here is Lady Wei) achieves justice for her and others through sheer wits and clever scheming, all the while being in the underdog position. Comic relief proper is part of the script too, with the main male and female characters, but not only them, providing humorous lines or instances.
Case in point, for the very different treatment of the same facts: on a trip down South, the Emperor Qianlong indulges in entertainment provided by prostitutes.
The dark "Ruyi's ..." treats this as the ultimate downfall, with the good girl Ruyi kicking out the prostitutes and confronting the Emperor with cutting a string of her hair, to make final her decision to separate from him as her husband.
Whereas the lighthearted "Yanxi Palace" had Lady Wei (here she is the good girl) joking about the incident and suggesting that as the Emperor was entitled to enjoy the company of beautiful young women, so she and the other concubines were entitled to enjoy the company of beautiful young males, so she asked for more eunucs for her palace. This made the Emperor clear the room of prostitutes himself, in frustration at the ideas Lady Wei put in front of him.
However, there is one major difference between "Ruyi's ...", on the one side, and "Yanxi Palace" and "The Story of Ming Lan", on the other side.
The first one is a sound story, well written, perfectly cast and superbely acted.
And yet, there is room for only one charcter development: the Emperor emerges as the only one who shifts gears and thus is the main cause for all the drama.
Whereas the second and the third productions are perfect all around, meaning that the character and story development does not stop at one, allowing for multiple stories and characters to converge onto the main storyline, thus making both these productions richer in context, heavier in meaning.
Anyway, a joy to watch and re watch all three of them.
I hope you would enjoy them as much as I did.