Tantei ha Mou, Shinde iru - Nagisa and Siesta! The story got complicated...
Tantei ha Mou, Shinde iru / The Detective Is Already Dead (探偵はもう、死んでいる) is a light novel series written by Nigoju and illustrated by Umibouzu that currently has 13 volumes (2019–present). I have read the first 11 so far, but I plan on catching up on the series soon.
The story follows Kimihiko Kimizuka, a young man who somehow always gets involved in some trouble for one reason or another. One of these incidents occurred in junior high when he was kidnapped and forced to carry a suitcase on an international flight. On that flight (which was hijacked), he met Siesta, a young woman of uncertain age who proclaimed to be a "legendary detective" and declared that she was going to make him her sidekick.
They spent three long years together solving cases all over the world, and then... she died during one of these missions, leaving him alone. He returned to Japan and started living in a state of apathy without much interest in anything until he received a request from a high school girl named Natsunagi Nagisa to find the "true owner of this heart."
Nagisa's life was saved by a heart transplant, and she feels that from time to time, this heart is calling out for someone. She wants to understand who the owner of the heart was. Kimihiko, albeit reluctantly, agrees to help her out and is thrown back into the world of detectives.
Things aren't so clear-cut, though, and there are many secrets behind what happened in those three years, many of which Kimihiko still doesn't realize. Is the detective really "already dead"? And if she is, what exactly killed her? Together with the three heroines who join him almost immediately (Natsunagi Nagisa, Yui Saikawa, and Charlotte Arisaka Anderson), he goes through a huge number of cases to discover the truth.
While the page count per volume is within the common average for light novels (around 300 pages), the volumes are dense with content, and it feels like you have seen a lot after just a single volume. I remember being shocked by how many twists and turns there were back when I read the first volume.
I am going to discuss some slight spoilers in this section, so if you haven't read the novel's first few volumes, it is probably worth skipping to the following paragraphs. The first story arc centers around finding out what happened to Siesta during those three years and why her heart is now residing within Nagisa.
I was honestly quite shocked by the many twists and turns regarding the identity of everyone involved. Seed was the centerpiece of the story; he was the incredibly perfect villain who would destroy the world if not stopped. Even the seemingly all-knowing Siesta was hard-pressed to find a way to outwit him.
The story felt natural, and you could see how everything felt very carefully planned by the author from the beginning. Nagisa being both Hel and Alice was an incredibly well-written twist that I wasn't expecting, and it really further cemented the fact that I love her as a character.
The first story arc eventually reached a fitting conclusion that cleared the main hurdles and left a bittersweet feeling. It was all perfect to me. However, the story then continued with a new thread to follow and the hope of fully bringing Siesta back to the others, and I feel that this second part dropped in quality.
The focus switched to learning about the role of Kimihiko as the "Singularity" and the new set of twists that accompany all the other actors (lots of other geniuses are introduced like Reloaded) in this new stage. Nagisa becomes the "Legendary Detective," and eventually, Siesta returns. We even get a time skip showing the three living and working together.
Hell, we even get Siesta searching for places where having multiple wives is allowed so that Kimihiko can marry both her and Nagisa (which would be my best possible ending for the three). It is great, and I still enjoy every moment of it, but I still think it lacks the "magic" that made me feel the first story arc was a "masterpiece."
Regardless of my nitpicking, I truly suggest you give this series a chance. The light novel is still one of the best series I have ever read, and I hope to come back to write more about it as soon as I read another volume.
