tl;dr: A mystery manga that has essentially no overarching plot, but consistently has solid well written cases. This manga is very much a hardcore mystery manga. The core of the story is purely a series of distinct cases with very little in terms of overarching plot beyond that. There are characters that repeat from case to case, but it's not really like they have much of a story beyond the cases so it mostly just amounts to relationships. There's a bit of romantic development between Hajime and Miyuki, but it's pretty slight and their relationship basically feels like it's in the stage right before becoming anactual romantic relationship for the entirety of the manga. With all the other reoccurring side characters, they get introduced and establish some sort of connection to Hajime, which stays the same for the rest of the manga.

For the most part, these characters are basically just meant to serve in roles that are necessary for the progression of the case which may be difficult to constantly have new people in, which can be seen in that when a character with an important role was murdered, another character that fulfilled the same function was quickly swapped in as a reoccurring character to replace them in a manner that felt pretty forced. The use of characters with relationships to Hajime is also used to allow for moments that add humor and lightheartedness in between the cases which are generally pretty serious, and though the comedy isn't that great, it does a good job at improving the pacing and preventing the manga from becoming completely dreary considering it's all about murder.

Now as for the mysteries themselves, they are all around really solid. They're clearly planned well from the start and executed well, making good use of being a manga by using framing, obscuration, etc. to the fullest. There's a decent amount of variety to them, wherein most of them are essentially closed room murders, but there are enough cases outside that to keep things fresh. In addition, there's usually something more to each case than just the trick involving the closed room murder. This often has to do with the motivations behind the murder and some sort of superstition being used to obscure things which helps make each case stand out beyond just the murder trick. The motivations of the culprit are also always developed in a lot of detail, wherein while they're almost always for the purpose of revenge with reasons that are meant to and generally do manage to evoke sympathy, there's a good deal of variety to why they're seeking revenge and how things proceed after everything has been laid bare.

I didn't know before reading it, but this manga is just the first series with two series that follow it, with the last case in this portion basically being a cliffhanger that suggests more of an overarching story might begin in the next series, so this isn't really something you can judge the end of just from this series as it's clearly not over. The art was decent and used well for it's purpose of conveying what it needed to for cases, but was not particularly great in and of itself.