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poison rationality

Summary:

Conan will do anything to get out of his math homework, including riding the subway at rush hour with an enhanced sense of smell in order to help Hattori find the sender of a mysterious letter, apparently.

Notes:

this is for deadfishmarinate, who asked for SGN au and Hattori & Kudou buddy cop case fic. hope you enjoy!

inspired by Phantom_Echo’s SGN verse! for those of you unfamiliar with the AU, here are the basics:
- Sentinels: enhanced senses, five levels of strength (level one has one enhanced sense, level two has two senses, and so on). Hattori and Conan are both Level 5, which mean they have all five senses enhanced.
- Guides: various mental abilities, ranked A-E based on how high a level of Sentinel they can pull out of a Fugue (when a Sentinel Zones in too much on one sense and become oblivious to the outside world)
- Neutrals: baseline humans
- World makeup is roughly 20% Sentinels, 40% Guides, 40% Neutrals; children are all Neutrals until they come Online sometime after middle to late adolescence (or don’t, if they’re Neutrals)
- Senes 1-5: Medicine that diminishes a Sentinel’s heightened senses down to normal human baseline. Rated 1-5 based on how many senses it works on. Not recommended to be taken for a long period of time. Not a substitute for a Bond. (Conan and Hattori are currently delaying Bonds for as long as possible for various reasons, and have at this point developed a tolerance for Senes 5, so now they switch between the other levels.)
- Bond: mental bond between Guide and Sentinel that allows a Guide to pull a Sentinel out of their own head if necessary. More serious than marriage - once you Bond, that’s that; there isn’t a way to unBond.

phew! sorry for the long note. on we go…

(See the end of the work for more notes.)

Work Text:

“Kudou, you gotta figure out who this letter is from for me! Oyaji said that he won’t let Ootaki-han slip me any info on active cases if I can’t figure it out, and since it’s your fault I got caught last time, it’s on you to do the legwork - ”

Conan blinks slowly and comes to the conclusion that, no, he isn’t hallucinating. Hattori is, in fact, standing in the doorway of the Mouri Detective Agency and had apparently once again not thought to let him know that he was coming up to Tokyo.

He’s also still yammering on about letters and his dad, and Conan has to suppress the urge to say, Gee, Hattori, how come your dad lets people slip you information? Couldn’t be me.

“…So are you gonna do it or not?” Hattori finally finishes, and he can never know that Conan had zoned out for most of his rant.

Conan stares blankly at Hattori, glances down at his kiddie homework, then back at Hattori where he’s still standing in the open doorway.

He shrugs.

Sure, why not.

Anything’s better than pretending he doesn’t know how to do long division.

The letter itself is encased in a standard envelope, the type that you can buy ten for a hundred yen at Daiso. Nothing special. It’s addressed to the Hattori family, typed up on a printed label. The return address just says Beika, though it’s handwritten and there’s sticky residue above it that indicates the person who’d written the letter had originally put a sticker there as well, though it had clearly fallen off at some point during transit.

Conan winces, the pads of his fingers scraping against the rough paper as he turns the envelope over - he’d taken Senes 3 this morning and it seems it’s only affecting his sight, taste, and hearing this time. On the bright side, it means that he can simply bring the envelope up to his nose and sniff it, then be rewarded with the scents of everything that’s ever touched it.

On the less bright side, he can smell everything that’s ever touched it.

Conan wrinkles his nose. People need to wash their hands more often. And maybe drop things less.

Underneath the terrible cacophony of smells, however, he could also smell the glue sealing the envelope together, and what the person who’d licked it had eaten for breakfast that morning.

Still disgusting, but probably moderately more helpful than anything else he could smell.

“They ate natto for breakfast the day that they sealed this,” Conan informs Hattori absently, who nods in agreement. Hattori’s pretending that he’s not interested in the case - well, it isn’t really a Case with a capital C, because it isn’t really urgent or murder-y, but it’s still technically a case to solve. And Hattori’s pretending that he’s going to shove all the work off onto Conan because it’s ‘his fault’ Hattori got caught wheedling information out of Ootaki, but he’s still going to jump back into the case in less than ten minutes because he just can’t help himself. Solving mysteries is in his blood as much as Conan’s.

Besides, Conan’s about eighty percent sure that this trip is less payback for some perceived blame and more ‘make sure Kudou’s still alive and breathing.’

He…appreciates it, probably.

It’s a distraction from his terrible life choices and the opportunity to spend some time with someone he doesn’t have to hide from, which is nice.

Also, Hattori smells good - like cedar and sandalwood - and it’s faint enough that it isn’t overpowering which is something Conan appreciates on days like today. He loves Ran, he does, but her perfume is an incredibly strong floral-y lavender thing that manages to sink into everything and gives him a headache when his senses are even slightly enhanced -

Conan blinks, shaking his head.

He can tell that he’s going to need to switch back over to Senes 4 again soon, because Senes 3 is no longer working quite the way it’s supposed to. It’s only mostly diminishing his senses instead of making them baseline Neutral - he can still hear Ran moving around upstairs, the near-silent shifts of the floorboards giving away her position, can taste in the air that the leftovers in the back of the fridge are on the verge of going off, can see the tiniest of smudges on the window where someone’s accidentally brushed against it -

He’s running out of time. Senes wasn’t made to be taken this long.

“Alright, Kudou?” Hattori asks casually, and Conan can tell that he’s deliberately keeping his hands stuffed into the pockets of his jacket instead of patting Conan on the shoulder or ruffling his hair.

Conan’s pathetically grateful for it. 

He had, in his hubris, chosen to put on a sweater that Ran had knitted for him, and somehow she had managed to use the scratchiest yarn on the planet. Even if he sits completely still and doesn’t move a muscle, the fibers bite into his skin, catch and yank on the little hairs on his arms, scrape against his cells -

But when he’d walked into the kitchen this morning she’d lit up like the sun, and even after he realized he was going to be in tactile hell he hadn’t had the heart to go change.

Instead, he’d put a cotton t-shirt on underneath and resigned himself to feeling like he was going to crawl out of his skin for the rest of the day.

He doesn’t regret his choice.

(He regrets it a little bit.)

“I’m fine,” Conan says. His words come out strangled and tense, so he clears his throat and says it again. “I’m fine.

(He’s really not.)

“Uh-huh,” Hattori replies, clearly unconvinced. He doesn’t bother to be subtle about giving Conan a concerned once-over, and it isn’t long before he’s locking in on the sweater and grimacing. But he lets it go for now, which is more than Conan could’ve hoped for, really.

“…Have you opened it yet?” Conan asks after a long moment of silence. Just because Hattori’s willing to let something go doesn’t mean he’s willing to change the subject himself.

Hattori looks at him, askance. “Open someone else’s mail?”

Conan nods, because - yeah, that’s what he’d just said.

“But - but that’s illegal!” Hattori blusters, waving his arms in the air like he doesn’t quite know the gestures to get his point across. “Punishable by a year in prison or a 200,000 yen fine!”

Conan stares at him for a long moment.

“Hattori, I’m illegal.”

Hattori blue-screens for a full 47 seconds. Conan knows, because he counts the faint ticks of the hands on his watch. Then Hattori shakes his head, trying to regain his composure. “Th-that’s different - ”

Not really.

Conan refrains from listing all the ways that Hattori is currently breaking and/or bending the law out loud.

(Knowingly obscuring the existence of a Sentinel, knowingly aiding a Sentinel in obscuring their level, refraining from taking a newly-Online Sentinel to the closest Center, attempting to Match with a Guide who was not of the same level, aiding in the creation of a false identity, property damage…)

They’re risking a lot more than a year in prison or a 200,000 yen fine.

…This is the line that Hattori doesn’t want to cross? Opening someone else’s mail, of all things?

Hattori sighs, tugging on the brim of his hat. “Also I lose if I open it,” he admits.

Conan just looks at him.

Hattori caves not five seconds later. “Fine, give it here.”

Conan gladly hands the letter over, then rubs the pads of his fingers on the hem of his t-shirt to get rid of the nasty feeling of the paper.

Hattori gives him a Look but doesn’t say anything, instead lifting the envelope up to the window. “Got a roll of toilet paper or something?”

Conan rolls his eyes and trudges to the bathroom to grab one of the spares. 

“You have Sight today?” he asks, handing it to Hattori and watching as he uses it to press the envelope to the window.

“Yeah, and good thing, too - otherwise this wouldn’t’ve worked,” Hattori replies, eye pressed up against the roll like it’s an extremely bulky monocle.

(Conan resolutely does not make fun of him for cosplaying Kaitou KID. Out loud, that is.)

“It’s folded, then?” Conan asks, and Hattori hums his agreement, tongue sticking out from between his lips as he concentrates. “Need an anchor?”

Hattori considers. “Wouldn’t hurt,” he says finally. “It’s harder than I expected to separate them.”

Conan offers his wrist obligingly like he does this all the time, and not like it’s happened a total of exactly once. “Sixty seconds?”

Hattori clicks his tongue, grimacing. “…Better make it thirty. I’ve been a little…” He makes an ambiguous gesture with his free hand that Conan takes to mean ‘spacey’ or possibly ‘too caught up in worrying about Kazuha and/or our ability to bond to actually control my train of thought for more than half a minute.’

Wonderful.

“Thirty seconds,” Conan agrees reluctantly, and Hattori takes his wrist, wrapping his fingers around it so that Conan’s pulse pounds beneath his fingertips.

“Thirty seconds,” Hattori mumbles one more time, then goes still as he dials up his eyesight.

Conan watches him closely, counting every quiet tick from his watch and getting ready to pinch Hattori or something if he gets too close to a Zone.

Nine, ten -

But honestly? It’s a little awkward. Conan has his arm stretched straight up in the air, which isn’t exactly the easiest of positions to hold, and Hattori’s got his face pressed up against a toilet paper roll on the window, so the position itself is awkward. But also, there’s only so long you can stare at someone’s face before it gets weird, even if they’re your friend. 

Twenty, twenty-one -

Conan has no idea what he’d say to Ran if she came downstairs and saw them like this. ‘It’s for a school project!’ probably won't cut it.

Though, on the other hand, he’s used worse excuses before and she’s believed it every time, so…

Twenty-nine, thirty.

“Hattori,” Conan says under his breath.

No response.

Fantastic.

“Hattori,” Conan repeats, using his free hand to tug on the sleeve of Hattori’s jacket. That should be enough to jolt him out of his head, but he doesn’t even twitch, and Conan’s heart drops to somewhere around his ankles.

“Hattori. Hattori!” Conan snaps, fingers trembling as he tries to pry Hattori’s fingers loose. 

No dice.

What the hell is he supposed to do if Hattori goes into a Fugue? A Rage? Conan's not a Guide; he doesn't have any training! And Hattori wants to avoid going to a Center for as long as possible, and -

Conan takes a deep breath to calm his spiraling thoughts, then kicks Hattori in the shin.

Hattori flinches. "Ow!" he complains, bending down to rub at the bruise that is no doubt forming beneath his jeans. "The hell was that for?"

Conan gives him a Look. It is a very expressive Look.

Hattori winces, rubbing at the back of his neck awkwardly. “…How long was that?”

“Fifty-three seconds,” Conan informs him, and he even manages to make his voice sound mostly even. “And you weren’t responsive. At all.”

“…Ah. I see,” is all Hattori seems to have to say for himself, and Conan isn’t at all satisfied with that answer but the way that Hattori’s shifting his feet slightly persuades him to let it go for the time being.

(Hattori isn’t handling being un-Bonded nearly as well as Conan was hoping he would. What did that mean for him? It’s not like there are tons of studies done on the effects of being an un-Bonded six-year-old Sentinel, since Conan isn’t supposed to exist, strictly speaking - )

”…Did you get anything from the letter?” he asks, instead of voicing the existential crisis he’s been having ever since he came Online. It’s not like Hattori isn’t aware of it already, anyway.

He gets a half-grimace in response. “Only a couple of phrases,” Hattori admits, like it’s something to be ashamed of, and it’s not. It’s really, really not.

“Well, what were they?” Conan prods, because he’s sure he couldn’t have done any better even if he knew how to dial up his senses the way that Hattori can. Especially not in less than a minute and risking a Zone.

“Just ‘please help,’ ‘think they were murdered,’ and ‘Beika 4-choume.’ No name or anything.”

Conan stares at him for a long moment. “…Yeah, but murder, ” he points out.

Hattori nods, like he’s got a good point.

(Because he does.)

(Ran’s right when she calls them mystery geeks.)

“Well!” says Hattori faux-cheerfully, and Conan knows that they’re not going to be talking about the whole almost-Zone thing any time soon. “To the 4-choume we go, I guess!”

The subway ride to the third district is - well, it’s better left unsaid, honestly.

There are so many smells, and Conan seriously didn’t need to know about the entire salmon the person sitting next to him had stuffed down the front of his shirt. 

Maybe he had smuggled it out of the grocery store. 

Maybe he was going to use it in a prank or something later. 

Maybe Conan will never be able to look at the jacket he’s wearing without smelling fish ever again.

(Conan certainly hopes he isn’t planning on eating it.)

And that’s to say nothing of the other passengers. 

There are a lot of kids, since the fourth block is where the Planetarium is, and their hygiene is not exactly stellar.

Suffice to say that by the time that Conan and Hattori reach the station, Conan is doing his best to breathe through his mouth only.

It’s only kind of working.

But, hey! He’s not passing out or anything! That’s a win!

(…It probably says a lot about his life that that’s a win.)

“You okay?” Hattori asks quietly, out of the corner of his mouth. He doesn’t look at Conan, instead scanning their surroundings, which is why Conan feels comfortable enough to allow himself to say, “Not really.”

He pauses a moment, swallowing deliberately so that his lunch doesn’t make a reappearance. Hattori still doesn’t look at him, but he does casually extend a hand towards Conan’s general vicinity. Conan takes it, half to maintain the charade of being a child who’s liable to wander off and half to give himself something to focus on that isn’t the hellish scratchiness of his sweater or the not-quite-identifiable stench of the trash can ten feet away.

“Thanks,” he mutters. Then, louder: “I’ll be better once I get some air.”

Hattori just nods wordlessly and asks the nearby station attendant for directions to the nearest park, which luckily happens to be not more than a five-minute walk away.

They sit down on a bench near the center of the park, and Conan takes a deep breath through his nose, filling his lungs with air that hasn’t been previously breathed by dozens of other people of varying states of hygiene. It’s wonderful, and he takes a few moments to just bask in it before turning back to Hattori. “Okay, what’s the plan? We don’t have a lot to go on.”

Hattori clicks his tongue in agreement, absently twisting his baseball cap so the bill faces forwards. “We know the person who sent the letter is probably located in this part of the city, and you said they had natto for breakfast, right?”

Conan nods.

“Well that, combined with the balance of their handwritten kanji suggest that they’re more than likely Japanese.”

Which doesn’t really narrow it down since they’re currently in Japan.

“Probably older, too,” Conan offers, “and maybe even retired, since the letter was handwritten instead of typed.”

So they’re looking for a Japanese person who is likely over the age of fifty. There are about twenty people in this park alone who fit that description.

Great.

They stare out into the park for a long moment. It’s a nice place - the grass is well taken care of, the walking paths are neatly marked, and the fountain in the center is gleaming like someone’s polished it recently. Hattori, Conan notes, is avoiding looking at the fountain as much as possible, probably because he doesn’t want to risk getting lost in the water’s glittering spray or the shine of the filigree decorations.

A good choice.

Finally, Hattori gets to his feet in a fluid motion that Conan’s a little jealous of, especially since he has to hop off the bench because his feet don’t quite touch the ground. Hattori benevolently doesn’t comment, instead announcing, “We’re gonna need to outsource.”

Conan nods in agreement. They need more information before they can start to narrow down their list of potential letter-senders.

“And what do we do if we need to find someone in a small neighborhood?” Conan asks, smirk tugging at the corner of his mouth.

Hattori grins back, a spark of enthusiasm eclipsing his concern at least for the moment. “Find the local little old lady.”

“Oh, you must be looking for Tanaka-obaasan. She knows everything!” says the extremely helpful college student jogging through the park. She gives them directions to the local little old lady’s house, and she even draws them a little map, just in case they get lost on the two-minute walk there. She also is not at all suspicious about why they might want this information.

She must be new to Beika.

“You can’t miss it! It’s the one with all the flowers,” she says, then continues on her run.

They indeed can not miss it.

“Got a mask?” Conan asks, voice strained, the second they step onto Tanaka-obaasan’s garden path. It absolutely reeks of flowers - a garden full of them, in fact - and an ambiguously floral perfume (separated from the smell of the real flowers by the faint scent of alcohol and minor chemical notes).

It’s.

A lot.

The subway, he could handle - he’s had a lot of unavoidable practice thanks to his time at kiddie school - and he can normally manage to sort of tune out Ran’s perfume after a few minutes but this is just…

Too much.

Hattori grimaces in commiseration. “Probably? Hold on, lemme check.” 

He rummages around in his pockets for a long moment, and Conan tries to just…not breathe. A mask won’t help a whole lot, not really, but it’s better than nothing.

“Aha!” Hattori fishes a slightly crumpled medical mask from the top pocket of his jacket and brandishes it triumphantly. Conan makes grabby hands for it, and sighs in barely restrained relief when Hattori just goes ahead and puts it on for him. Normally, he’d be irritated about the indignity of being treated like a child incapable of putting on a mask correctly, but at this point he’s just happy not to be smelling the cesspool of floral scents quite so strongly anymore.

Before he can thank Hattori (mostly by giving him a Look and then not kicking him in the shin again), the door to the house flings itself open and a little old lady wearing a loud floral dress bustles out.

Good. At least they're in the right place.

“Oh!” she says as soon as she sees them on her front path, pretending she hadn’t been peeking at them through the curtains the moment they’d stepped foot onto this street. “I’m terribly sorry - I didn’t see you there!”

Conan blinks rapidly, having not expected the sudden barrage of English. Hattori recovers quicker, replying with, “Apologies, madam, but we were wondering if we could ask you a few questions about the neighborhood?”

(Conan is inordinately jealous of Hattori’s English. It’s a lot better than his, though to be fair Conan is mostly self-taught.)

(Although…somehow it sounds different from normal…? Conan can’t quite put his finger on why, exactly…)

Tanaka-obassan’s hand flies to her mouth in exaggerated surprise. “And you speak English so well! Of course, do come in, do.

“Thank you, madam,” Hattori says, and - wait a second.

“Why is your accent in English suddenly British ?!” Conan hisses under his breath as he and Hattori enter the house behind the old woman.

Hattori blinks rapidly, then at least has the decency to look sheepish. “I… may have been mocking Hakuba a little too often…” he mutters under his breath.

Conan glares at him, definitely not envious at all.

(He is. He is so jealous that Hattori can speak with Sherlock Holmes’ accent, especially when Hattori doesn’t even like Doyle in the first place. It’s wasted on him.)

Before Conan can murder Hattori with his eyes alone, Tanaka-obaasan closes the door behind them and ushers them into a small, chintz-covered nightmare of a kitchen. She sits them down at the table, then putters about the kitchen making tea, nattering on all the while about the unseasonably cold weather. Apparently it wreaks havoc with her bees.

“You have an apiary?” Conan asks, suddenly interested and keen to show off his weirdly extensive and usually useless English vocabulary.

Tanaka-obaasan shakes her head regretfully, placing a clear glass teapot filled with what she has assured them is ‘the best Earl Grey tea I’ve managed to find in Japan’. “No, not as such,” she says a bit wistfully. “It’s just the two hives I have in the back garden. I’m lucky to have them at all, quite frankly, especially in the city.”

Yeah, Conan doesn’t even want to think about how many permits she must have had to apply for.

“Back when I was a girl,” she continues, “my family used to have acres and acres of wildflowers! Oh, it was beautiful… And the bees loved them, of course, so in the summer we’d hear them buzzing around, all busy. I think we even had a noise complaint once!”

She sets a small pitcher of cream on the table, accompanying it with a bowl of sugar and a tiny jar of honey not more than three centimeters tall. “We made the best honey in the city, once upon a time. And while I don’t regret marrying my husband and moving out here, I did miss my bees, so for our anniversary one year he managed to import the plants from my family’s old garden. He was such a kind man…” She delicately wipes a tear from her cheek. “Oh, that’s quite enough about me, I think. What was it that you wanted to ask me?”

She pours tea for her guests, then Conan gets up and pours some for her. It’s only polite.

“Have there been any weird deaths around here?” he asks, and Tanaka-obaasan  stiffens abruptly. Hattori elbows him in the side and he almost drops the teapot. Conan twists to glare at him, then remembers.

Oh, right. 

They’re here about a letter, not the murders. Whoops.

“I-I don’t…” Tanaka-obaasan stutters, looking from Conan to Hattori and back again. Conan stifles a snort. Right. The woman with binoculars beside the window doesn’t know about mysterious deaths in the neighborhood. He definitely believes that.

“What Conan-kun here means is,” Hattori corrects, giving Conan a Look, and Conan has to resist the urge to look off to the side and whistle innocently, “someone around here wrote my dad a letter about some potential murders and we’re trying to figure out who it was. The return address got peeled off at some point, so all we know is that they’re somewhere in Beika, 4-choume.”

“Hm…” Tanaka-obaasan ponders for a long moment, and Hattori takes the opportunity to take a sip of his tea. He freezes, and Conan has the hilarious experience of watching as Hattori tries to keep his face blank while he sets his cup back onto the table and reaches almost desperately for the honey.

Tanaka-obaasan doesn’t seem to notice, staring into her own cup as she stirs in a truly heinous amount of milk like the answers might be written in the swirls. 

“Well,” she says finally, “I suppose there have been more deaths around here, though they were all elderly so it wasn’t much of a surprise, I’m afraid. There wasn’t anything to indicate murder, at least not that the police found.”

Right. Because the police are competent enough that they don’t need to be led around by the nose by teenage detectives in order to arrest the actual culprit.

Oh, wait.

Hattori moves to take a sip of his tea - a polite, noncommittal response - when Tanaka-obaasan’s hand flies out and knocks into his cup, sending it flying through the air for a split second before it crashes to the tabletop, spilling everywhere. Somehow it manages to stay in one piece, which is impressive.

“Dear me,” Tanaka-obaasan says, dismayed. “I really am too clumsy sometimes. No, don’t get up,” she adds when Conan moves to help her try to contain the spill. “Please, let me just…” 

She takes a roll of paper towels from the cupboard under her sink and does her best to mop up the spill before it sets into her baby blue tablecloth. The lace doilies on top are a lost cause already.

Conan glances at Hattori curiously, because shouldn’t he have been able to see that coming and react accordingly? But Hattori just stares at Tanaka-obaasan, brow furrowed in contemplation.

…Why? Why had she knocked the cup from his hand? It had most certainly been a deliberate movement - there has been a determined glint in her eyes a moment before she moved. And, besides, she wasn’t the type to accompany her speech with big animated gesticulations - and even if she were, she hadn’t been speaking at the time. 

So what was the point?

Tanaka-obaasan finds another teacup in a cabinet - it has a similar pattern to the one she’d almost broken, so it’s probably part of a set.

“I’m terribly sorry,” she says, smiling self-deprecatingly. “It’s just, I saw that there was a smudge on that cup, and I couldn’t bear for a guest to drink from something dirty.”

Yeah, right.

It doesn’t take a genius to realize that’s a clumsy cover-up.

“Why don’t you take that mask off, dear?” she suggests, turning her focus towards Conan (likely in a bid to divert their attention away from her weird flail a moment ago). “It must be hard to have your tea with it on.”

A timely breeze blows in a myriad of scents from the garden, and Conan sneezes violently in response to both the question and the smell.

“Conan-kun here is just getting over a cold, and we didn’t want to pass it on to you,” Hattori explains, passing Conan a disposable tissue from the box on his side of the table.

“Oh, how sweet you are, taking care of your brother like that!” Tanaka-obaasan gushes, and Hattori and Conan instinctively glance towards each other.

They don’t - what??

They definitely don’t look similar enough to be brothers.

Oblivious to their silent incredulation, Tanaka-obaasan continues: “I might be an elderly woman, but I promise you that my immune system is hardy enough to withstand a pesky little cold!”

Well, then.

Conan can tell that he’s not getting out of here without at least pretending to drink some tea, and it’s not like he has a better way to test his hypothesis.

He pulls down his mask, and immediately the scent of the tea assaults him. He has to hand it to Tanaka-obaasan, though - it is good tea. There’s no stench of chemicals or artificial flavors, just some bergamot and black tea leaves.

Underneath the almost overpowering scent of the tea is a fainter floral scent. It’s not Tanaka-obaasan’s perfume - that’s artificial enough that Conan can recognize it and do his best to filter it out. 

Conan frowns, concentrating. Where is it coming from…?

“Oh, of course, how silly of me!” Tanaka-obaasan exclaims. “Have some sugar, dear.” She pushes the small bowl of sugar towards him, but Conan doesn’t take any. Instead, he reaches for the small pot of honey.

“My grandson used to love a few lumps in his tea,” she continues. “And, do you know, you remind me of him quite a bit…”

Conan just has enough time to wonder if he has yet another doppelgänger running around Japan before Tanaka-obaasan manages to nudge the jar of honey with her elbow, sending it clattering to the ground. The lid shatters to pieces, and the honey begins to seep out of the container.

“Oh dear,” she says, hand flying to her mouth. “Today really doesn’t seem to be my day…”

Conan isn’t paying attention to her anymore - instead, he’s focused on the honey slowly spreading across the floor. That’s where the faint floral scent is coming from, and he’s pretty sure he can recognize it now that the lid is gone.

That’s…not great.

“I’m sure I have some more somewhere, ” says Tanaka-obaasan, slightly flustered, as she places a paper towel over the mess and bustles around the kitchen looking for more honey. “It must still be by the hives… I’ll be right back, please excuse me.”

She hurries out of the kitchen, a woman on a mission, and Conan’s gaze follows her.

“Hattori,” he says urgently, as soon as she leaves the room, “there’s oleander in the honey. I can smell it.”

Kyouchikutou, - oleander, in English - is a plant poisonous enough that a single leaf can be fatal to human beings. Even honey made by bees that are primarily fed on it can be deadly. It can be treated, of course, with no long-lasting effects other than a few days in the hospital, but that’s only if it’s caught early enough and the doctors actually know what they’re treating. It’s not like oleander poisoning is common in the Tokyo area - maybe closer to Hiroshima they would catch it, but there are so many illnesses or poisonings that present with low blood pressure, stomach pains, or fainting.

There’s more than enough oleander in the tiny pot of honey in front of them to kill half a dozen adult humans, and it’s already half empty.

It’s just their luck to stumble across a serial killer while trying to find the author of a mysterious letter, honestly.

“Where the hell have you smelled oleander before?!” Hattori demands quietly.

“Hawaii,” Conan deadpans, only about half sarcastic, then hisses, “Listen, we need to get out of here before - ” He cuts himself off abruptly, because Tanaka-obaasan suddenly reappears from the garden. She’s holding a frying pan in one hand - what, does she just keep it outside? - and she steps purposefully towards them, a hard glint in her eyes.

She lifts the pan, ready to bring it down on top of Hattori’s head because she thinks that he’s the bigger threat. She thinks that because he’s tall, strong, and able-bodied, he’s therefore the one she needs to take out first if she wants to continue living outside a jail cell. Normally, she’d be right in her threat assessment, because who sees a six-year-old as a threat?

It’s a mistake she’ll never make again.

Conan only has approximately two seconds to lift his watch, aim, and fire, but somehow he manages it.

Tanaka-obaasan’s hand flies to her neck as the needle pierces her skin. She barely has time to shoot Conan a murderous glare before the fast-acting sedative enters her bloodstream and her grip on the frying pan loosens. It clatters to the floor, and Hattori jumps at the noise. He turns in his chair just in time to instinctively catch Tanaka-obaasan before she follows her frying pan to the floor, sound asleep.

“That,” Conan finishes, lowering his watch. “Before that happens.”

Hattori groans. “You’re going to hold this over my head forever, aren’tcha.”

Conan beams up at him innocently. “I have no idea what you’re talking about, Heiji-niichan! But we should probably call the police now.”

“Hattori-kun?” a quiet voice asks from the garden next door as the police lead a newly-conscious Takana-obaasan into the back of their patrol car. 

(“It was an accident - I promise, I had no idea that my honey was poisonous - !”

“Tanaka-san, we found a hit list on your fridge door.”)

Hattori and Conan turn at the sound of his name, and the voice is revealed to belong to an elderly Japanese woman. “Oh, you must be his son! You look so much like your father when he was your age…”

Hattori blinks, nonresponsive.

Yeah, same.

“I was his homeroom teacher in high school, Hagane-sensei, though I doubt he’s ever mentioned me,” she continues, “and - well, I take it you got my letter?”

Ah. The mysterious letter-writer appears.

“Yes, Hagane-sensei,” Hattori says, finally finding his voice.

“Oh, good! Well, I remembered that he liked mysteries when he was in my class. There have been quite a few strange deaths around here recently, so I thought that he might like to poke around! Does he still like mysteries?”

“…He’s the Superintendent Supervisor at the Osaka Prefectural Police Headquarters,” Hattori replies distantly. He sounds like he’s having an out-of-body experience, and, yeah, Conan feels that.

Hagane-sensei claps her hands together. “How wonderful! I knew he was going places. Did he send you to help?”

Hattori opens his mouth, and Conan just knows he’s about to say something uncomplimentary about his father, so he steps on Hattori’s foot, hard.

“He sure did!” Conan says, mostly to cover up Hattori’s quiet yelp. “The police just arrested the murderer, by the way.”

Hagane-sensei blinks in surprise. “Well, don’t you two work quickly!”

Conan fishes the letter out of Hattori’s pocket (ignoring the quiet “Hey!” in his direction) and represses a flinch and the terrible, terrible sensation of the paper against his fingertips. “Would you mind signing the envelope so Heiji-niichan’s father knows we found you?”

(Also so Hattori’s dad could compare her signature on the outside of the envelope with the one on the inside, thereby negating any argument that they hadn’t found the right person.)

“Oh, of course!” Hagane-sensei pulls out the pen holding her bun together and writes her name on the envelope. “Thank you very much, you two. Would you like to come in for some tea?”

Hattori and Conan exchange a glance.

“…I think we’ve had enough tea for today, thanks, Hagane-sensei.”

Notes:

title from what i THOUGHT we’re the lyrics to a panic at the disco song (and a fun pun lmao) but apparently it’s “poise and rationality.” i feel lied to.

backstory i couldn’t fit in: hagane-sensei and tanaka-obaasan have a rivalry over who can be the nosiest old biddy in the neighborhood. when people who have offended tanaka-obaasan start dying, hagane-sensei sends the letter to heizou because she thinks she might be next. little did she know that tanaka-obaasan wasn’t going to waste her precious poison honey on her bitterest rival - no, that was reserved for people who cut in front of her in the convenience store one too many times or who speedwalk faster than her when she’s out exercising. for hagane-sensei, on the other hand, tanaka-obaasan planned to stage a suicide in which hagane-sensei strangled herself to death using her own luscious locks of hair. just for that extra personal touch.

thank you to Phantoms_Echo for allowing me to write in your universe!

also thank you to kuroko99, Mamshiba101, and Taliya for beta-reading!

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