If you go into nigozyu's light novel The Detective Is Already Dead looking for a mystery, you may find yourself disappointed. Although the book deals with some of the tropes and elements of the genre, it's much less a mystery novel and more a mildly supernatural science fiction story that takes as its base the concept of detective and assistant duos in the Holmes and Watson vein. The basic premise is that Kimihiko, the Watson figure, lost his Holmes a year prior to the story's opening, and now he's somewhere between “grieving” and “at loose ends.”

The detective in question was Siesta, a girl roughly Kimihiko's age when they meet at fourteen, who worked to counter a secret evil organization known as SPES. SPES, named after the Latin word for “hope,” claims to want to help humanity, but their tactics seem to contradict that; one of their major achievements in the novel is creating human/monster hybrids. Kimihiko, who has been an extreme trouble magnet his entire life (i.e. accidentally walking into crime scenes and drug deals), encounters Siesta because he's somehow ended up ferrying a mysterious attaché case on an international flight. During the flight, a cabin attendant comes on the intercom to ask if there's a detective on the plane, and it turns out that there is – and that she's the reason Kimihiko's there in the first place. That detective is of course Siesta, and she conscripts Kimihiko as her assistant. The two take down Bat, the SPES agent, and kick off a three-year-long crime-fighting career.

At this point it is worth mentioning that the description of Bat's implanted tentacle is somewhat less goofy in the original than it ends up looking in the anime adaptation of this part of the novel. The book says that the tentacle comes out of his ear, rather than enveloping the entire ear, which frankly makes a lot more sense. In a later chapter, a second SPES agent has a tongue tentacle that is grafted onto his own tongue; this again makes more sense than a separate bladed tentacle implanted alongside his tongue. Slightly silly as the entire “giving humans tentacles as weapons” thing is, there is a real sense that the author gave this some serious thought – and within the context of the story, it seems entirely plausible that one of these SPES agents could take down even someone as competent as Siesta.

Another place where the book really succeeds is in the way Siesta is so present throughout the story. Even though she's dead, she's the character everyone thinks about and references, and all roads ultimately lead back to her. While not quite on the level of Tohru's mother in Fruits Basket (the best example of an absent character taking up space in a story), it still works well, showing how the memory of this one person drives the entire story. In the case of Nagisa, that's much more literal, given her link to Siesta, but with Kimihiko and Charlie, who both worked with her up until the day of her death, it's Siesta's shadow hanging over them that keeps them moving forward. Charlie, who styled herself as Siesta's apprentice rather than assistant, is haunted by the detective, and she moves forward in order to bring herself closer to the person she so admired. Things are more difficult for Kimihiko; he's unable to see himself as anything but Siesta's assistant, and despite the fact that he's a capable individual, he cannot move beyond the idea that he has to work as someone's right hand. He can't understand that Siesta taught him enough to keep going on his own without making himself subordinate to another detective.

Simply put, The Detective Is Already Dead is less about solving mysteries and more about Kimihiko realizing that he can be the hero of the story. From what we see of Siesta in flashbacks, it's clear that she's known her time is likely limited and that she's prepping Kimihiko to be able to carry on in her absence, perhaps seeing that what he thinks is his bad luck is actually the universe telling him to be a detective. That's something that Bat, who does come back in the novel's present setting, is also very aware of, and Charlie as well. Other elements of the story support this idea, most notably that Kimihiko is, by the end of the book, surrounded by three attractive girls, at least two of whom have attempted to put moves on him. It is a nice twist on the basic harem formula, because Kimihiko isn't the bland protagonist all the girls are inexplicably attracted to – he's got a personality and noticeable things going for him, he just doesn't realize that with the detective dead, he's now the protagonist of the story.

The book does suffer from its tenuous use of actual mysteries, a couple of which rear their heads and are almost painfully obvious in their solutions. nigozyu also falls into that category of light novel authors who thinks they're a bit more clever than they are, and the story suffers from the usual overwriting and density common to less well-put-together light novels. There's also a small disconnect between the text and the illustrations; nigozyu describes Siesta's dress as looking like a military uniform while Umibōzu's art shows it much more on the Gothic Lolita side.

The Detective Is Already Dead's first novel isn't terrible, but it also has some issues that keep it from being unequivocally good as well. It takes some interesting twists on established genres, and that lands it firmly in “good enough” territory. Just don't go in expecting a mystery and you'll likely find things to enjoy.