"Death Comes as the End"
It's just a feeling, but I have a suspicion a majority of posts on snow-themed mystery stories on this blog are actually published in the warmer half of the year...

Fortunately, the old lodge is 500 meters away from the new lodge, and everything should still work there, so they decide to move to the old lodge: the men go first to make sure heating there does work and to carry the kerosene, while the women will follow later with the food supplies. The men have just arrived at the old lodge and starting to prepare for their stay here, when the women in the new lodge use a walkie talkie to contact the men: one of the skiers has gone missing, and there's blood in the hallway. Two of them return to the new lodge, while Hajime and the municipal official stay in the new lodge, but then they discover the body of the missing skier: her head has been cut off, and placed on her lap! When everyone has moved to the new lodge, they learn that their radio is not working and the skis have gone missing, making it impossible to contact with the outside world nor to go down the mountains themselves. By discussing the case, they discover that while nobody has an actual alibi for the murder, as they don't know what time exactly the victim was killed, everyone does have a soft alibi: nobody could've carried the body from the new lodge to the old lodge unseen: the round-trip would've taken quite some time, but nobody was gone for long times/went unseen between the time the victim was last seen alive and the time the body was found. Soon one of the women suggests it's the headless skier: two years ago, a team of skiers got stuck on the mountains when the weather suddenly changed for the worse. Stuck in the cold and with no way to call for help, the team's leader volunteered to ski down the mountain alone to get help. However, after she left, a rescue helicopter found the remaining team members, but the leader never made it off the mountain alive. Only her cut-off head was later discovered: someone had strung piano wire between trees, so when the leader was hurrying down the mountain to get help... Some say a headless skier is now haunting the mountains, but is this ghost also responsible for the murder, or is this the work of a living and breathing human?
You know, The Headless Skier Murder Case, which spans volumes 16 and 17, has a funny setting. Closed circle settings in this series are often either on an island or somewhere in the mountains... so why not set the story on a mountain, on an island, writer Amagi must've thought. But if this fusion of ideas sounds like he was trying to cook something grand, I'll have to disappoint you, as The Headless Skier Murder Case is a surprisingly simple case, basically revolving around one single trick. The mystery revolves around the fact nobody is ever gone long enough to allow them to carry a dead body and their head to the other lodge and return, which thus gives them all an alibi. This mystery is repeated later, as another dead body is found, this time at the new lodge while everyone was staying in the old lodge. The problem is that it is really just this mystery that drives this story, and the solution is not only a concept we have definitely seen previously in this series, in those stories we ususally get more than just this one idea, so there they can at least benefit from being presented as more difficult puzzles as they are interwoven with other ideas. Here, the problem is presented so bluntly it's nearly impossible to not guess what's going on. The big surprise is actually when the murderer is revealed and they start explaining their motive (yes, it's revenge, it's always revenge), as we learn how this person had been directed by a certain character to commit these murders: while the identity of this person won't be revealed until the next story, I *kinda* suspected who it was, though I thought it would be cheap, and then it turned out it was really that person and now I have no idea how this is going to develop in future series. The final volume of this series, The Sealed Space in the Sky Murder Case, starts with Hajime confronting his old nemesis The Puppeteer from Hell, a "crime consultant"-esque character who helps people bent on revenge by supplying them with perfect crime plans. While the Puppeteer has been in prison all this while, Hajime knows the Puppeteer has disciples: they call themselves the Olympian Gods, with the Puppeteer as Zeus the omni-god and Hajime has already encountered and captured a few of them. But after a conversation with the Puppeteer and a hint from his cousin Fumi, Hajime realizes one of the Olympian Gods, Hephaestus, is actually a person near him: he deduces Hephaestus is someone at his work, and that Hephaestus, with the help of another inside person at the company, has been keeping tabs on Hajime, which is why all these murder cases have been happening to Hajime each time he's gone on a business trip. Hajime has a pretty good idea of who Hephaestus's accomplice in the company must be, but the moment he decided to keep tabs on her, she ends up dead: ostensibly via suicide by throwing herself off the rooftop of the company building. She had borrowed the key to the rooftop to water the plants there, and as the key was found in her pocket, the rooftop door was indeed closed/locked and the guard kept the spare key safe, it looks like a genuine suicide, but Hajime knows better: Hephaestus must have killed their accomplice to silence her, and used a "sealed space in the sky" murder trick to challenge Hajime himself. But how could Hephaestus left the rooftop after the murder, as the door to the rooftop was locked (with the victim down below in possession of the key) and no way to reach the surrounding buildings? Hajime knows this is his chance to nab Hephaestus, and narrows the pool of suspects to a handful, but the list includes not only his direct superior, but even his faithful subordinate Marin...For a story that is mostly about very quickly wrapping things up and features a very simple trick for its main mystery, I have to admit I liked it better than I had initially expected. A lot of the initial chapters is about trying to bring back the whole story about the Olympians back to the foreground again, as it's not been a priority plot element throughout, usually only being mentioned at the end of a case if the murderer happened to be one of the Gods and forgotten again, but here we get a crash-course on the related previous events and a rather cool deduction by Hajime about who he thinks Hephaestus' accomplice is and why. This is the type of hinting and plotting you very often see in Conan, using its serialized format to plant clues within various stories, across a longer period of time, but Kindaichi basically never uses this, with far more compartmentalized storytelling (and very loosely connected stories), so it's cool to see it utilized here. The 'Sealed Space in the Sky" mystery is relatively simple, with rudimentary visual clues and like the previous story in essence a one-trick-pony, but I do like that the focus in fact does not even lie on the howdunnit, but the whodunnit, as we see Hajime then utilize the howdunnit to cross off the suspects of the list, using Queenian logic to identify Hephaestus. This series more often uses a straightforward way to identify the killer (X making certain utterances/doing certain things/in possession of certain things), so seeing a Queenian chain, even if very short, is pretty cool. The identity of Hephaestus is perhaps not as interesting as the direct aftermath, as the gameboard is reset to lead into the next series. We do get a brief explanation why Hajime swore off solving mysteries long ago, but we don't get the details, but then it's basically off to the next series. And very literally too, as this volume also included the first chapter of the new series: Kindaichi Papa no Jikenbo ("The Case Files of Dad Kindaichi"), in which Hajime has been a father for a few years while running his own detective agency. Hajime's new client instructs him to go a certain place on a certain date, and because Hajime is a very responsible father and definitely knows what's going to happen whenever he goes to a remote place, he decides to take his son with him and the two find themselves arriving at an old decrepit hotel that's absolutely safe and where no murders will happen...
Anyway, that wraps up Kindaichi 37-sai no Jikenbo. I have to admit, the initial shock factor of seeing a suddenly aged Hajime quickly waned after the realization that storywise, these cases weren't that different from the usual affairs save for a few rare exceptions like stories with a more urban setting. Some ideas never really come to full fruition I think, but as a limited series, it at least had more direction than the 20th Anniversary series or 30th Anniversary series. The last story at least does a lot to make it feel more like a series on its own, so that helps, though I can't feel super excited about the deal of the Olympian Gods basically halting midway, and I'm still not sure what to think about that one character turning out to be one of the Gods too... I guess I'll have to keep on reading the new series to see if Amagi decides to actually end some of these plotlines anytime soon (I mean, I know Conan is long, but at least it has arcs that actually start and end).