Major plot threads spoilers below, although I try to be as vague as possible.
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Though I enjoyed many aspects of this drama, such as the cast and characters and the sweet and emotional scenes, I have mixed feelings about how the second half of the drama unfolded to the point where I was no longer actually invested and only fastforwarding scenes to find out what happened and how it will all be resolved. The saving grace of this drama is the acting from the four main leads, especially zheng yecheng and janice wu.

The drama starts off as a detective-type historical with a focus on fantasy as ye yuanan and zhao lanzhi solves cases that happen to intertwin with the life of mu le, an amnesiac servant boy bought by ye yuanan, and ming hui who has her own missions to find the Nine Divine Beads and thus she undermine zhao lanzhi at every turn. That's how it starts and is fine. It was intriguing and compelling (although sometimes it feels like I'm just tuning in to an episode to see which case will come up; each case is only connected by the Nine Divine Beads), especially when finding out more about what mu le's true identity is as he has shown signs of being more than an ordinary person. However, his identity is very slowly hinted at during the first half. The first half instead focuses on building the romantic relationships between mu le and ye yuanan, and ye yuanan and zhao lanzhi, and zhao lanzhi and ming hui--which will lead to angsty moments in the second half, which some decent payoff.

The relationship between mu le and ye yuanan has good tension because mu le is only a servant whereas she is a noble lady. although mu le (and I think ye yuanan) never feels like that should be a problem, society and everyone else does. mu le becomes frustrated at his identity as a servant. ye yuanan is oblivious of her own feelings--as she is tomboy-ish--and instead just opts to showing her care through her actions. mu le also becomes frustrated with his identity because it leads to bullying. he just wants to be with ye yuanan--he's very devoted--but is faced with all these external barriers and the obliviousness of ye yuanan.
ye yuanan and zhao lanzhi's relationship is pretty cute and I'm not even mad why she cares about him so much and vice versa. I'm fine with how it developed, the feelings it went through, and how it ended.
zhao lanzhi and ming hui was an interesting one because I didn't see it coming although I do like enemies-to-lovers trope. Their mutual dislike/distrust is a very fun dynamic, although it starts to become suffocating at a later point as ming hui, being an antagonist-type, becomes super toxic in trying to own zhao lanzhi.

Regardless, the relationships between the characters developed well and the story was interesting until toward the second half of the drama (mostly toward the end).

I was completely happy to see mu le recover his identity and go back to his rightful place and I liked that the setting moved us to a different place in the suoluo kingdom. I was fine with that plot move.
This was a chance for ye yuanan to struggle deeply with her complex feelings for mu le: the sense of betrayal, the sense of care and love. It's a lot to handle and unfortunately, I don't think janice wu pulled it off as well as it could've been. It could've been the fault of the director and editor and script writer too, but this kind of tough and complex situation really needed a great actress and janice wu didn't make me feel compelled but rather annoyed. (If you want to see a great scene that handled the betrayal and love and horror, just rewatch Goodbye My Princess when Xiaofeng realized that her lover Gu Xiaowu is the one that destroyed her grandfather's clan. That scene is just stunning and heartbreaking and incredible.)
ye yuanan was repetitive toward the last like 12 episodes and, although I understand that she is very bitter about the betrayal, she came off as idiotic at times and childish where it wasn't enjoyable anymore. I was also hoping that this second half would be a chance for ye yuanan to grow compassion; as she is now undercover as a servant and is treated badly just like mu le was when he was a servant, I thought there would be some connection there and some enlightenment and empathy toward mu le. Instead, ye yuanan just came off as constantly complaining and still so stubbornly arrogant. On one hand, it's align with her personality, but at the same time, it feels like she just didn't develop as a character.

As I said earlier, I was fine when the plot took us to the suoluo kingdom, but then there was time-travelling, which I threw up my hands and was like "Fine, we're doing this." I was fine with that plot turn too--but then they made it happened three times. Three times! ye yuanan kept saying that she could accomplish the mission back in time, but then fails--and they STILL let her go! I don't care how compelling her argument is--that she's responsible for mu le, whatever--it's just so idiotic that they let her go again and again when it was clear to everyone that she wouldn't be able to accomplish the mission. Instead of having her go back and forth in time three times, they should've just had it happened once and have her go through all of that stuff in one go.

The saving grace of the second half of the drama is mu le in his true place and his identity. he looks really great all dressed up, confident, and elegant. Not much else was very cathartic toward the end, sadly, not even my feelings for mu le and ye yuanan helped me through it. It was just zheng yecheng pulling me through to finish it.