The Border-Line Case

"Space, the final frontier."

"Star Trek"

This has nothing to do with the book of this post, but: Mu is one of my favorite characters from Saint Seiya, and I love his attacks Starlight Extinction and Stardust Revolution.

Hase Homare is a tour attendent on a special monitoring trip for the first low-cost space carrier: a group of guests have been selected to come along to spaceship "Hope!!", which will bring them to the space station hotel Stardust, where they'll enjoy a few nights before heading back to Earth. The service will start officially soon, so this special trip is one last check to see if everything will go as planned. There are just a handful of guests coming along, most of them who have paid a lot of money to be able to see Earth from space (and one student who just happened to win a contest), so there are only two staff members on Hope!!: Homare and the captain Itou, a former astronaut, who after a period of seeing the bottle too often, has gotten his life on control again, eager to prove himself to his family and the rest of the world. The trip to Stardust goes perfectly, with all the guests arriving safely at the hotel, where they are greeted by the hotel staff who had arrived earlier. The hotel resembles a cone with a halo around it: the main cone building, with the dock, storerooms and all the equipment and machines, has mainly zero or low gravity, so people are advised to use the special belts they have to anchor themselves, though there's is gravity in the halo part of the building, which is where the guests rooms and lobbies are. While Homare goes off to write up a report on the trip for headquarters, Itou starts carrying out rations they brought on their ship to the storerooms, but when Itou doesn't return, Homare goes looking for the captain, only to find Itou dead in one of the storerooms. However, the scene is bizarre: it looks like Itou hanged himself with a belt... only you generally can't hang yourself if there's no gravity. Staff members all have special smartwatches that monitor their movements, and it appears nobody of the staff came even close to the storeroom around the death of Itou, so that seems to clear them, so does that mean one of the hotel guests is the murderer? Or was it suicide. The management back on Earth however order Homare to continue as planned, as too much is at stake on this first test trip. When a second death happens however, the hotel staff members use escape pods to return to Earth, citing their legal work conditions (only allowed x hours in space), leaving Homare and the guests alone in the hotel. Homare can operate "Hope!!" all by himself up to a degree, but the guests all seem reluctant to return to Earth now, as they have just arrived, so it's decided they stay in Stardust as initially planned, but then more deaths occur while trapped up in space in Momono Zappa's Hoshikuzu no Satsujin (2023), or as the book also says on the cover: Stardust Murder.

Momono Zappa is a game scenario writer who made their debut as a novelist in 2021 with Rouko Zanmu ("Dreams Are All That Remain To The Tiger Who Has Grown Old"), a cool mystery novel that utilized a wuxia fiction background. Hoshikuzu no Satsujin similarly has a mystery set in a rather unique location: a space station. At the same time, we're not talking about the super far future: the world portrayed in this book is certainly quite close, with low-cost space carriers probably appearing soon, and the setting is far closer to our current society than say the mobile suits in Gundam Wearwolf, also a mystery set in space. So for a great part, a lot of the setting of Hoshikuzu no Satsujin will be almost the same as ours, with people needing Wi-Fi to do livestreams for back on Earth. In fact, Momono does a great job at portraying the practical difficulties of operating such a space station, occasionally touching upon the technical and scientific details about how things are working at Stardust. At one point, the space station also loses its contact with Earth, leaving Homare unable to call back to headquarters and inform them about the subsequent deaths after Itou's death, and the idea of just... being stuck in space without a way to call for help is just horrible. Of course, they have escape pods they could use, but Homare does emphasize that the escape pods just shoots them towards Earth to the ocean, so it could take days before the pods are actually retrieved and they're saved, so it's a last resort. So there's a lot of mileage to be taken from the concept of a closed circle situation... in space.

Like in Rouko Zanmu, Momono does like focusing on their characters and what drives them: each of the guests, but also the staff members have their own specific reasons for wanting to come to space, and it's what also informs their actions while being confronted with their predicament. Like a lot of these And Then There Were None-esque stories, you'll be looking out for motives in each character's backstory for wanting to commit murders while being in a closed circle situation (and in space, no less!), and the interplay between the various backstories does allow for a bit of going back and forth between suspects, though I'll be honest and say that motive-looking is seldom my favorite part of a mystery story. Those who want a more introspective mystery however, might find something they'll like here, as of course, the dream of going into space is one that has mesmerized people since ancient times, and you can easily imagine how everyone holds very different thoughts about what space could mean to them.

As for the mystery, a lot of the immediate riddles Homare and the rest of the guests are confronted with, are about howdunnits: whether it was a suicide or murder, how could Itou have been hanged, if there's no gravity to do the hanging? Another guest is nearly suffocated in his room, even though they locked the door before going to sleep (i.e.a locked room), and more such curious incidents happen. The tricks behind these occurings are... perhaps not surprisingly if you think about it, but I have to admit I was surprised how technical some of these tricks were. In a way, Momono does hint at these tricks, but the jump from being presented clue A and me deducing that could result in trick X was way too far for me, so I personally didn't always feel as impressed with the trick as I could've been: perhaps a more science-minded reader will love what Momono does here, as the tricks utilized by the culprit does make good use of the space station setting. I wouldn't say this is hard science by the way, just some things aren't as intuitive to my feeble humanities mind as for the author.

There's a direct sequel to this book by the way, Rousoku was Moeteiru ka (Is the Candle Burning?), which focuses on one of the guests of the hotel after returning to Earth. I have no idea whether the semi-scifi setting of this book is continued in the second book, so in that sense, that is kinda what interests me.

Anyway, Hoshikuzu no Satsujin uses a unique setting, but without going overboard or alienating readers with the lite scifi setting. While mystery-wise, I felt some of the tricks were a bit too technical for me to feel intuitively clever, as a book about people being trapped in a space station under deadly circumstances, I found the book quite captivating, and I blazed through it in no time, because I wanted to know how it'd end. I will probably pick up the sequel in the future too, so expect a review of that book too. 

Original Japanese title(s): 桃野雑派『星くずの殺人』