I think the reason to read this manga is for Minase Masara's art. As usual, it does not fail to amaze in its beauty and delicacy. However, did the story fair as well? Not really. And I blame it on the fact that it wasn't written by Minase sensei. This manga is the story of "Kairi," who works as an assistant for an art professor. Kairi's main job is to collect data about the Rose Thief, an art thief whose signature is a rose, to help the police investigation. There's one big problem: Kairi is the Rose Thief. Moreover, it's not only the police who
are after him, but also the Russian maffia, and they sent Herve to catch Kairi. But Herve doesn't seem to act like a maffia (or at least that's what Kairi thinks--I wonder from where he got his information about how maffia act, because in yaoi they usually act the way Herve does :D). There's something about Herve that just draws Kairi in and they sort of start hanging out (but we are not really shown them hanging out or why Kairi is being drawn in, just sort of told so).
It doesn't sound that awful, but the thing about stories that feature "bad" people is that they need to give as something so that we don't hate the characters, unless it's meant to be some dark piece of writing, which Missing Code certainly isn't. But we don't get that something that will make us like Herve, and though we hear Kairi's story, it's so briefly touched upon that we can't really feel it, so it's hard to empathize with his character. Good examples of how writers create lovable pieces centered around "bad" people are Totally Captivated (Hajin Yoo), where we are not just told but shown both the protagonists' past so that we understand how they got to where they are now and can empathize with them, and Tightrope (Natsume Isaku), where we are aware that the characters are part of the yakuza but it's more like an empty title, particularly considering how against violence both protagonists are. In Missing Code, there's nothing like that, so for almost the entire manga I was more preoccupied in trying to suspend my disbelief than actually enjoying the story.
It's kind of sad saying this, but my favorite part of the manga was the ending, because the romantic tone that prevailed the story actually fit this part. I think the artists should have just stuck to the sort of story that is told in the last chapter if they wanted a romantic manga, and if they wanted a drama/mystery, they should have gotten rid of the romantic tone that gave off a feeling of dissonance.