Again: There are only ever four actual solutions to locked rooms. One, the culprit is still inside the room until its opened, but either hides or tricks people into ruling them out. Two, something (not per-se the culprit, although it probably is) seals the room from the outside; this ranges from elaborate setups with keys and string to something as simple as ramming the wall to knock over a shelf. Three, it's not actually a locked room - there was some way to the culprit was able to get in and out. Four, the murder is performed from outside the room, using a trap or a golem or the Power or a sniper bullet.
We'll give these four solutions labels.
1) Killer Never Left
2) Lock Trick
3) Secret Exit
4) Remote Murder
And though I wouldn't really count it myself, I suppose if you want to be anal about it, there's also a fifth possible solution, although it's less a locked room trick specifically and more of an anti-solution that in a novel I'd consider pretty cheap: When the locked room is never witnessed personally at all, and is simply the result of a lie or a misunderstanding by those who supposedly did. We'll call this:
5) Didn't Even Happen
I have read hundreds of mystery novels and watched a truly unaccountable number of terrible dramas, and I can say with complete confidence there exists no solution with in the human imagination that doesn't fall into one of these camps, even if the story is explicitly supernatural. Killer is a vampire and escapes by turning into mist? That's Secret Exit. Contrived Mmicroartifice poison kills someone a week after its been ingested? That's Remote Murder. Suicide? That's Killer Never Left.
I know I'm beating a dead horse here, but let's review the facts of Bardiya's murder one more time. Myself, Ran, Kamrusepa, Fang, Ezekiel, Ophelia, Ptolema, Seth, Theodoros, Bardiya, Linos, and Lilith and her mother were together in the dining hall and kitchen, having brought the barrier (which can only move through objects which are completely stationary - in other words, unliving) with us from Bardiya's room. Suddenly, it was struck by a gunshot passing through the hall and conservatory. Ptolema and Seth, who had been in the kitchen getting supplies along with Theodoros and Bardiya, rushed out to see what was going on, and after a moments it was decided that Fang, Kam, Ezekiel and I were to go out to investigate.
Linos briefly dropped his barrier as we departed. We traced the impact holes to Bardiya's room, and then to a pistol that seemed to have been rigged using an elastic band to fire after a certain amount of time. At around this time, we heard Seth calling for us to come back, and after the barrier was briefly lowered again, returned to the sound of a dull thumping from inside the kitchen, the door to which was unlocked. Ptolema used the Object-Manipulating Arcana to open, and then we discovered the body - half-turned away from the window, face completely crushed on one side and partially crushed on the other - and Theodoros against the opposite wall.
Afterwards, we used the Anomaly-Divining Arcana, and determined that only two arcana had been used in the applicable time frame we couldn't account for: An earlier use of the Object-Manipulating Arcana to seal the door, and then the World-Deafening Arcana, to silence the scene of the crime. We also performed an examination of the body and found nothing amiss other than the fatal wound. Later still, we observed security footage that showed the side of the building at the time the crime was committed, though we did discover a small amount of blood on the bushes outside the window.
That's it, I think? Yeah, I think that's it.
So. Of that, what did I know beyond all doubt? Strictly speaking?
Firstly, what I'd seen with my own two eyes. I'd seen the four of them go into the kitchen, and heard and seen the light of the gunshot. I'd seen Linos's barrier go down as we left, though not, technically, when it went back up behind us. I'd seen the pistol, though not any specific details until Fang had laid hands on it. And on the run back, and I'd seen the barrier active before it was brought down again, and this time had confirmed it was reactivated right away.
The door had already been locked upon our return; according to the Anomaly-Divining Arcana, both incantations were activated a few moments after Seth and Ptolema had rushed through the door, though we had no way of knowing the specific location of the caster save that they had to have been inside the barrier. I'd seen Ptolema unlock it, and of course, I'd seen the scene of the crime - though due to fainting, hadn't personally confirmed the state of the body until later. (Though that's redundant because:)
Secondly, what could be confirmed by the rules.
Rule 6. All corpses identified by the protagonist (ie: Me) were assured to be dead. I don't know why - maybe some unquantifiable part of my consciousness was starting to wrap itself around the unspoken metaphysics of this place - but I knew this 'counted' here. Bardiya, when I'd seen him, was dead. A real corpse that had belonged to a real person, no tricks. That much was certain.
Rule 7. No secret passages could be missed if a room where a murder took place was investigated. Nahmi had confirmed this rule applied specifically if a secret passage was used. So if it was a true locked room, there was no way the culprit could have got in or out that I wasn't already aware of.
With all that established, which of those five solutions were plausible?
1 was, on the surface of it, the most likely. Theo, for all he might have seemed earnest during his final confession, could have just been lying. Or, as I'd hypothesized several times, Bardiya could have simply killed himself for some reason. Smashed his own face aggressively into the barrier unto death.
However, at this point, the vibes felt like they leaned against this possibility. After all, if Seth had died in the same way in Kamrusepa's loop, that meant that everything that suggested Bardiya's mental state might have been more unstable than it appeared - his room, his participation in the boy's conspiracy despite his personality - was irrelevant. Even if some horrible secret had been revealed to them in the form of a hidden message or something, it felt difficult to believe the two would have the exact same response. That officially placed this possibility in 'fallback' territory', in my book.
2 had to be viewed a little abstractly, because in this case the 'lock' in the locked room wasn't the physical lock - that was no mystery - nor even per-se the barrier but more the idea that the culprit might have created an exit for themselves using some fiddly method. It was, I supposed, not impossible that someone had employed the Object-Manipulating Arcana purely as a red herring. Even if it'd been forgotten in the heat of the moment, we all had master keys. Someone could have, say, locked the door with the Power, then unlocked it with a key, killed Bardiya, and then locked it again on the way out. Or vice-versa - killing him in the even narrower window of time directly after Seth and Ptolema had left.
This would be an interesting trick if it were the case, because it would allow the culprit to obfuscate the time of the murder as well, if only by a little bit... but even so, this also felt like a stretch. The whole area was too tightly observed - even after our search party had left, there still would have been a score of people in the dining hall. Even with the panic, it would be almost... no, likely outright impossible to slip through the door again without anyone noticing.
The only way I could feasibly believe the culprit could pull of a trick like that would be if virtually everyone left behind were accomplices, and simply overlooked it altogether. In other words, Didn't Even Happen. But that felt even less likely than the suicide possibility, especially with Theo, who was in the most pivotal position to witness anyone coming through the door, feeling so unlikely to have been an accomplice that the possibility felt almost redundant. Like, if I was willing to believe that, why not that he'd just been the murderer?
So, it was probably reasonable to rule that out too, unless everything else was a complete non-starter. As a grandmaster arcanist, it was my professional opinion that no one could have breached the barrier using some kind of trick that wouldn't show up using the Anomaly-Divining Arcana, which left the only possibility was the window... and that was ruled out by the camera footage. So, there you go. Not 2.
Since I'd already ruled out Didn't Even Happen on my way here, that left two more possibilities: Secret Exit or Remote Murder. The first was mostly ruled out by the rules, but the second brought me back to the hypothesis I'd made shortly after my meeting with Neferuaten. That someone could have used some kind of indirect, mundane mechanism to commit the murder from within the barrier but outside of the locked room, specifically above, passing through the barrier during the windows in which it was taken down.
It felt like a long shot, but it was the best hunch I had.
"Kam," I spoke up.
"Mm?"
"I guess you won't be able to confirm this completely, since Linos could have done it differently," I said, "but do you happen to know if the barrier could have extended to the floor above?"
"Ah, I see what you're thinking." She smiled brightly. "Well, why don't we go see for ourselves?"
I frowned. "Or you could just answer and save me the trip up the stairs."
Kam scoffed. "Su, you realize that being corporeal here is largely optional, yes?"
"I feel enough like a ghost already without floating through everything, thank you very much."
She rolled her eyes as I sat up and moved towards the door.
It was a room I'd never gone into before - someone might have mentioned it? - but directly above the dining room turned out to be a library. Assuming the books within were the originals, the contents were significantly less academic than those in the main hall. It seemed to be mostly genre fiction and popular science and history, plus a shelf of the classics in the rear left corner. The kind of thing a rich person who didn't actually read books would stock a room with for the purposes of aesthetics.
Anyway, I'd been expecting a door at the north end to lead to the room in question, but instead there was a window, and that should have been enough to address my theory right then and there. But of course I went over to confirm it, and discovered directly why Kamrusepa had seemed so amused by my idea a moment prior.
Which is to say: There was nothing above the pantry. I'd never noticed, but the second floor of the abbey was smaller than the first, with much of the rear consisting of only a slightly-angled, tiled roof. The barrier did extend over it, but less than I'd hoped for on account of its thickness. A child could maybe fit inside if they were lying down, and even then it would be a stretch.
Still, some possibilities remained.
Kamrusepa had appeared behind me. "Any questions?"
"Can you get inside it?" I didn't turn to look at her. "The roof, I mean."
"Well, as I'm sure you've already assumed, the Order replicated this structure - twice - rather than recreating it from scratch."
"More than an assumption," I corrected her, turning away from the glass. "In my loop, Neferuaten explicitly told me."
"There you go, then. She walked past the shelves and joined me, gesturing at the exterior. "Because this building - or rather, the idea of it, I suppose - has such a storied history on top of being a hotspot for Spectating blocks, it's in fact been rather difficult to perfectly reconstruct its internals. But..." She floated through wall like it was nothing, descending down to the roof, then flicked her hand to cut a cross-section of it open. "If you consider the size of the bricks used for the abbey, the space between the ceiling of the kitchen and the apex of the roof, and the overall construction and weight of the materials, there's almost certainly extensive wooden scaffolding inside that would make it completely impossible to enter."
"As a general rule, sure," I conceded. (Despite my no-doubt-transcendentally-vivid descriptive work up until this point, you may not be surprised to know I knew absolutely nothing about architecture in any practical sense, so I had no way to infer whether or not this was actually true.) "But you could make an exception for one spot if you built it that way in advance, right?"
She raised her eyebrows. "You're suggesting the entire thing was erected with the explicit intent to perform a specific trick murder decades later?"
"Yes."
"Hm." She pursed her lips. "You really might have a knack for this."
I gave her a deadpan expression.
She giggled a bit, then continued: "On this particular occasion, though, my guess is that you're parking up the wrong tree," she said. "Even assuming all that happened, there would still be two obstacles. Firstly, even discounting the internal obstacles that should be there, the gap between the ceiling and the roof would still be rather narrow. You might just about be able to squeeze a more slender adult in, but it'd be a murderously tight fit. They'd barely be able to move."
"They could have greased themselves up," I said, and then - suddenly feeling I needed to justify this further - added, "that happens sometimes. In mystery novels."
"You don't think that would, I don't know, leave some signs?" Kam suggested, amused. "Stains, perhaps?"
"Look." I frowned at her. "I'm just floating possibilities, here. Things that could have happened purely physically, even if it's... not likely."
She snickered. "If you say so."
"You said there were two reasons," I said, moving things along.
"Right, yes." She walked over the edge of the roof, looking down at the side of the wall. "The other reason is that there aren't any practical ways they could have got in to the ceiling, at least without using the Power. Because of the structure and layout, there's not an abundance of potential access points. There's the room you're standing in now, the side of the building... and that's it. Nowhere where one could get break in without making a lot of noise very close to where people sleep."
"Could there have been a secret passage?" Before she could interrupt, I continued: "Unless I'm misunderstanding, the rule only applies to space where the crime actually happened. This is sort of an edge case, isn't it?"
"It is, but in a bit of a different way than you're thinking," she said. "You're right that there would be nothing to preclude a secret passage here, but there are ways in which this whole line of thinking - assuming you're going where I think you are - sort of falls afoul of the rule."
"How so?"
"Because unless they're using a ranged weapon, then any kind of physical object is sort of treated as an extension of the culprit," she explained, raising a finger. "Say the culprit punched a hole in the wall and used it to impale the victim with a spear, then pulled the spear back out. That hole would become the 'secret exit' through which they 'escaped', thereby meaning it would inevitably be detected."
I scoffed, though the idea did make sense. I myself would have put a scenario like that in the 'secret exit' category more often than I'd have put it in the 'remote murder' category. "You could have saved me some time and told me this earlier."
"There's an element of ambiguity to it." She moved the finger to her lips, pausing for thought. "Rather-- Sometimes, if the mechanism through which the weapon passes is considered to be intuitively obvious, the world's rules won't intervene to direct the observers attention to it explicitly. Say you have a room with a grate in it, and the culprit stabs someone with a syringe through one of the holes. Because the grate isn't hidden in the first place, you can't exactly 'find' it, so it's not counted."
"That's so vague," I complained. "What counts as implicit? Lots of rooms have little holes or cracks in the walls, or things like that. Where do you draw the line?"
"It's just a matter of whether the observer has seen them already or not," she answered with a shrug. "But it means the obvious can sometimes go overlooked."
So if there was some route of access through the ceiling I'd already noticed, I wouldn't be assured to pick up on it in relation to the murder.
I shook my head. This was too fringe, and unrelated to my present train of logic anyway.
"Anyway," Kam said, "to go back to your theory, while we can't prove it, a secret passage into the ceiling cavity has never been observed or appeared in any record or account." She strolled back towards the wall, phasing through. "So I'd say a secret passage is unlikely."
Well, shit, I thought. I guess this whole line of thinking is a bust too.
Defeated, I wandered back downstairs., Kamrusepa again not bothering to follow directly What was left, other than relying on suicide or Theo being a liar?
There was, I supposed, another angle to 4 that had crossed my mind previously. Because of the mechanics of the barrier, we've established it would have been impossible for the culprit to have been hiding in the room beforehand. The only way to be 'exempt' from it would be to have been completely motionless, which was for humans was impossible.
But what about something that wasn't alive?
"It's cheap, and feels a little dumb," I said to Kam as I returned to the dining hall, she of course having beaten me there. "But could a golem have done it? Just, I don't know, hidden in one of the cabinets or the pantry, then jumped on the victim's backs and smashed them into the barrier?"
"On paper, there's no reason why that couldn't have happened," Kam replied, and I could tell the stupid face she was making exactly where this was going. "But do you want to know something interesting?"
"Do tell."
"Across all our collected accounts, including the books, almost no one is ever murdered by a golem. Especially in a deliberate setup like this."
I furrowed my brow. "That's... ridiculous."
"Ridiculous?"
"It doesn't make any sense," I clarified. "The whole sanctuary is full of golems. Not just the defensive ones which literally attacked us in the hall, but the ones that served us food, the cleaning ones - I saw one of them while I was with Neferuaten... I still don't understand how exactly the rules are supposed to have could or couldn't do, but I can't think of anything under them which would render their use unacceptable. But you're telling me they never kill anyone?"
"Oh no, don't misunderstand. The golems do kill people quite a lot, especially the one's that patrol the halls," she explained. "They just don't participate in any planned murders. Well, again-- Almost never."
I scratched the side of my head. "So the culprit either can't, or won't, use them."
She shrugged. "Presumably."
"Any sense of why?"
Kamrusepa folded her hands together in front of her face pensively. "Well, the conclusion I would be led to by Occam's razor would be they don't have any direct control over the sanctuary, and are purely an opportunist, taking advantage of the chaos for their own goals. That said, there is another possibility I've also dared entertain."
I nodded. "That they're choosing not to?"
"Indeed."
If that were the case, there were only two motivations I could imagine: That they either had some kind of complex about putting trust in machines, or it was important to them, for some reason, to commit the murders personally. Obviously whoever was responsible had to be extremely resourceful, and already interested in using elaborate tricks for some reason rather than killing in a purely utilitarian fashion, so I found this easier to believe than the idea that they wouldn't have been capable or at least rigging them sometimes like the one Ran and some of the others had worked on in my loop.
Obviously it couldn't be a matter of pure visceral spite or bloodlust - wanting to see their target die with their own two eyes - even though the creation of the loop itself did seem to amount to just that. After all, they employed accomplices. So it felt a bit fuzzy.
Still, there was a more pressing question.
"When you say 'golem'," I asked, "does that refer to the puppets Zeno and the rest of the Order were employing, too? Or only non-human creatures."
"That's a trickier affair," she replied, holding a finger to her lips. "The books are a tad bit difficult about the false bodies. They only report real murders - where someone genuinely died - and while they treat everyone with a body as a character, at least as far as we can tell, the perfunctory and dreamlike quality of the prose means that people just sort of... disappear from the narrative when its done with them. So it's almost impossible to determine-- Well, not just this, but all situations in which identity is ambiguous."
I frowned. "Huh."
"My guess would be that they don't count, for what it's worth," she added. "But that's only based on my own theories. Take it with a grain of salt."
I thought about all this for a moment, then shook my head. All of this was beside the point. If a golem was out of the question, what about a trap? No, that was no good either. I couldn't think of any mechanism that could be employed to repeatedly ram someone against something that wouldn't leave some kind of trace after the fact. It was possible it was all cleaned up while I was unconscious, but that just led directly back into everyone being in some big conspiracy and the resulting contradictions. Besides, if Kamrusepa's account was to be believed, that would do nothing to explain Ptolema's death, which had been explicitly the work of the Power.
I could only think of one more possibility that wasn't completely fantastical.
"I'm going out the window," I mumbled, walking to the other side of the dining room.
"I'm really not understanding these lines that you're drawing, here."
I floated outside, looking down at the rosebush. My thought was that, if it were sufficiently high, then maybe someone could have lied down in it as part of some... I don't know, pseudo-trap. Maybe they ran a length of wire tied into a noose through the underside of the closed window, then tugged on it when their target was ensnared. They wouldn't have even needed to see what was going on.
Yes they would have, my inner skeptic reminded me. You were just thinking about Ptolema's murder 30 seconds ago.
Right, right. Okay. Maybe they were carrying a mirror, then, that let them see up into the room despite their position. Or... Well, maybe instead of covering in shock at the back of the room, Ptolema had leapt over and tried to free Seth, leading the culprit to hastily cast the Object-Manipulating Arcana and tossing a pot at her head as an improvised weapon. I liked that, actually - it lined up with the difference between her and Theo's personalities, and explained why death would have been off-theme.
This explanation would cover the blood splotch on the bushes too. The more I thought about it, the more I liked it, even if it initially felt awkward.
Unfortunately, my optimism would prove short-lived. This whole thing was predicated on the idea that if someone got deep into the bushes, then they might be able to do all of this while invisible to the camera. But the hedge turned out to be shorter and denser than I'd expected, and looking up at where the camera was supposedly posted overhead the angle felt even more awkward. And when when I tried to lower myself into the vines, I not only realized there was no way to do so without crushing the whole thing into a weird, obviously- noticeable shape, but also got a cut on the side of my leg for my trouble.
"Fuck!" I cursed.
Kam held a hand to her mouth in a ladylike fashion as she laughed at me, and I glared at her.
"I can't believe you're still not using any kind of barrier more often than not," she commented. "You're practically asking for someone to pull some dreadful prank on you, you know."
"I haven't figured out how to do anything skin-tight that doesn't get in the way of things I'm trying to do," I dismissed, crouching over and nursing the wound. Ugh, it's torn my tights, too. This sucks.
"I take it you were trying to see if someone could have hidden from the cameras?" Kam asked. She seemed oddly curious for something that was obviously barking up the wrong tree.
I just nodded, feeling deflated.
So. That was possibility 4 eliminated too. Which left nothing but the wrong-feeling solutions I already talked about, and... locked room bullshit, basically. You could squeeze in a Culprit Never Left Theory if you were willing to embrace fantastical pulp - maybe Person X can been hiding in the rear corner of the ceiling, dropped down when the barrier was lowered, and squeezed into one of the larger cupboards when it was raised, before finally fleeing altogether when Mehit demanded it be taken down again the better part of an hour later. Maybe they'd taken a drug that rendered them physically dead and motionless, allowing the barrier to pass over them; a particularly ridiculous breed of Lock Trick. Maybe it involved magnets. (Magnets were the last refuge of a truly desperate mystery writer.)
None of these would be the answer, but you could always squeeze through some stupid theory in a situation like this; reality was too vague for any locked room to be truly perfect. But in real terms, I'd hit a wall.
"Alright," I moaned, throwing my arms into the air in resignation. "I'm stumped."
Kam scoffed. "Oh, don't say that. You've been at this for less than 10 minutes."
"But I can't see any way it could have happened." I looked through the window, taking in the scene once last time. "The culprit couldn't have been hiding in the room in advance because of the barrier. They couldn't have come or gone through the door because of the size of the crowd. They couldn't have done something through the ceiling - or, presumably, the walls - because of the rules and the structure of the building. And even if the culprit had the key to the window or used the tiny space under the frame, they couldn't have done anything from out here because of the camera." I sighed. "I can't see what I'm missing."
Kamrusepa tutted a few times playfully. "Goodness me, Su. After that game, I really thought you'd have a bit more fight in you then this. You're falling at the first hurdle of the trick."
"Stop being so condescending."
She didn't seem much affected by this demand, shaking her head with a smile. "How do you generally perform your reasoning, if you don't mind me asking?"
"I don't understand the question," I said, folding my arms. (I probably could have if I'd thought about it for a second, but I was feeling pretty burned out.)
"How do you reach conclusions logically to the best of your ability, I mean," she clarified. "Do you work your way down from deductions to inductions to abductions? Do you establish a list of your priors and the evidence and then contrast them? Or maybe for something like this you focus on empathy, putting yourself in the positions of the victim and the culprit?"
"I-- I don't know. I'm not into logic-as-philosophy in the way you are." I frowned. "I try to think of exactly what I'm completely certain of first, then use that to identify the possibilities, to make sure I'm not missing anything. Then I just... vibe out which feels the least implausible."
She arched an eyebrow. "So a first principle-led approach? That's not really what I'd call a complete theory of logic. You're just doing deductions and then trusting your gut. That's like pouring stopping halfway through a math problem and then rounding it to your nearest lucky number."
"Kam, I'm not some fucking rationalist," I said, a little peeved. "I'm a biophysicist who reads mystery novels."
She sighed, rolling her eyes. "Well, I can teach you some bloody inference methods later. For now, you should re-examine your priors. I'm not sure you've established what's certain as well as you think?"
I frowned. "What are you getting at?"
"You said the camera is the reason the culprit couldn't have done anything from out here?"
I nodded.
She pointed skyward. "Go be the camera for a second. See if anything pops into your head."
A part of me wanted to just rebuke her and just say what she was getting at, but admittedly, there was a small part of me that kind of did feel bad about the idea of failing to meet Kamrusepa's expectations. Living here so long had definitely intensified her constant smugness about her own intellectual rigor, and I really wanted to get my footing enough to start noticing the ways in which she was being a blowhard with tunnel vision, because I was sure that hadn't changed either.
So, grumbling to myself, I flew into the air. And instantly, I realized.