My true rating: 7.15/10
*The review may contain details that you would not understand if you did not watch the drama since it's vague, but not spoiler-worthy.
This drama was actually pretty good for one of these typical lower budget rom-com "period" dramas, and I think the main leads dubbed their own parts, which is always great.
Fantasy elements are always a plus for me, and this synopsis was semi-new compared to the other gods/celestial being or material arts type of drama when it includes fantasy or "power" aspects.
I feel like this drama could have had the potential to become an 8 or higher if they filled in more gaps instead of having the viewers make assumptions by increasing the budget and making this 32 episodes or even just making the first few episodes (which were only around 20 minutes each) longer.

Story/Plot:
The romance aspect was decent, but the non-romantic parts were skimmed over too often. For instance, there was the "crime"/"murder"/"detective" bit in the drama, which was not really focused on much and I think it would've added more to the story if some parts were actually explained, but maybe it's just me that enjoys the crime-murder-mystery genre and wanted more of it.
I also would have liked some logical reason or explanation to better understand the side characters. Some questions that were left to be guessed or assumed: why did the brother become so greedy, why is the emperor so lonely, what did Su Wu Quan (Su Yin Yin's father) write during the exam that made him better (since this was a major catalyst for the events that followed), etc.

Characters/Acting:
The acting for each individual character was great, but the chemistry was just okay.
To elaborate:
The female lead: got annoying quickly since she was the typical stubborn girl in these types of dramas, was not anything extremely special, but I was able to put up with her since the drama was focused on the romance more than other parts. If they focused on the other stuff, then I would most likely drop the rating for this drama.
The male lead: poor dude :'( if you watch it you would know why but I liked the fact that he was able to become a scholar in the imperial court by assisting the emperors and crown princes of the family, but I would have liked more explanation on how it happened
ML+FL: Separately the characters were believable, however, the chemistry together was passable, but not amazing.

Notable supporting characters:
Tang Lin Lin: Her character was the only one that had some explanation for why they did seemingly odd things at first and could have been developed into a more complex character and focused on "worldly" (as in pertaining to the world without taking time periods into account) issues (sexism) and we always love a girl who has martial art skills.

Emperor (Li Si, played by An Xiao Ge no MyDramaList page yet): I just feel bad for this emperor, he is the only emperor in C-dramas ("real" emperor as in one that is actually ruling/governing the land and not focused on a girl) that is legitimately alone and lonely as in not even a concubine lonely, but this is also what makes him one of my favorite characters because he was loyal in that sense by making his brother the Crown Prince. I wish they could have dived more into his character instead of making theories about everything. His (and the Crown Prince Li Ji) admiration for their master (male lead) is cute and this emperor is one of the most human emperors in cdrama-land so far.

Mo Cheng Feng: He was actually the reason I started this drama (which was already on my list but got pushed up) but a bit disappointed to find out that he was not the main lead. His development was interesting, but I think a few minutes about him before everything happened would have made it more understandable (or less depending on the producers/directors/screenwriters). There is a love-hate-hate feeling towards him, but it might just be the unrealistic character, but I guess karma worked out.

If you read all this, sorry for being vague or confusing, but I did not want to spoil anything.

Music: Usually I don't say much about music, but I really liked the songs in this, especially the main one 傾世谷雨来 used in the drama and it's different from typical Chinese drama songs since usually, they all sound similar/familiar to each other, but this one was different.

Rewatch: I never rewatch dramas so this is just used to make the desired "Recommended score"

Overall: This is a very romance-focused, maybe one of the most romance-focused dramas I've watched, which took away a lot of the potential this drama had. It's a nice refreshing difference compared to other Chinese dramas in the same category as this based on the setting of the story, which is what kept me going.