The title made me expect that this would be a period detective drama of sorts, and there are some aspects of the detective genre at the start. However, the more interesting part of the series actually start when the detective genre conventions get ditched as the characters become embroiled in political intrigue.

I'm somewhat undecided about how good the story is. On the one hand, it is quite an engaging story. On the other hand, it can be infuriating at times because of the characters' occasionally illogical behaviors. Despite having anticipated that there would be people coming to rescue a prisoners, Tang Fan someone sits down in the prison, talking to the prisoner as though he were waiting for the people to arrive to rescue the prisoner (and kill him in the process). Yes, a large number of people had to be deployed for some other mission, but to make no attempt to hide the prisoner elsewhere or take care of his own safety is just senseless behavior coming from a person who is supposed to be really intelligent.

The story actually gets better after a while, as the different cases investigated by Tang Fan get more complex and are intertwined. The series does have characters who are likely to be endearing or intriguing to the audience. This helps in the series' less interesting parts. Tang Fan is cute (to me) and intelligent although he can be silly and even exasperating at times. The eunuch Wang Zhi, is intriguing because he is by turns ruthless and compassionate. He is politically astute and knows how to maneuver his way around. However, he is also fiercely loyal to the emperor. The other main character, Sui Zhou is the one whom I actually took time to get used to because of his deadpan expressions (physically and verbally), but he is quietly caring rather than emotionless. I think the actor does quite a fine job of portraying a soldier with PTSD.

This is a censored adaptation of a BL work, and the BL is largely taken out. We do get occasional hints of it, especially in the later parts of the series. It seems that there was some indecisiveness as to whether to give Tang Fan a female love interest instead. There are points when Tang seems to be romantically interested in Dora but eventually this does not get anywhere (possibly because someone realized that turning BL relationships into bromance isn't quite as bad in the eyes of many viewers as turning BL into straight romance). As for Tang's relationship with the imperial guard, Sui Zhou, even if the relationship has been transformed into bromance, it would have been good to show the intimacy between them early on. Instead, this gets shown clearly (whether as bromance or potential romance) somewhat late in the series.

The image of Sui Zhou putting a cloak on Tang Fan followed by a shot of them standing next to each other towards the end of the last episode does hint at something between them despite being subdued. It gives a nice conclusion to the series and leaves their relationship somewhat open-ended.