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Published:
2024-03-11
Updated:
2025-12-09
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74,365
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20/?
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Summary:

When a horrific chain of murders linked only by precious gems forces Dazai and Chuuya to work together once again, they find that nothing could've prepared them for their undercover identities.

Dazai and his fake husband Chuuya are the newest rich residents in hotel Hermitage, to the average eye doing nothing but wining and dining on their honeymoon but in reality they're doing everything to find a killer who has exhausted every other method.
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"As we were walking past them earlier, I overheard Mrs Miller talking about us to the people at that table.”

“Why is that a problem? The plan was for them to introduce us to more people.”

“The problem is that she was telling them that she'd never seen us kiss before and considering we were on our honeymoon she thought we’d be rather affectionate, even in public.”

Shit

“Shit Dazai, no.”

“Kiss me while everyone’s looking.”

Notes:

Hi, this is my first attempt to write a fanfiction so it is a work in progress but if this does gain traction i assure you i will write quicker than i ever have. That also means I'm new to using Ao3 so I'm still getting used to how stuff like tags work

This idea was originally a book prompt using OCs but i decided to give it a shot as a fanfiction first, so for the sake of the story and really its just relevant to the beginning but the port mafia and armed detective agency are located in London. It's where I live so it just means I can make the details as accurate as possible.

Also with every new chapter I'll add a song recommendation, its just a little thing that makes me feel more 'connected' with the work idk I just always think it's cool when someone does it

Chapter 1: Long live convenience

Chapter Text

“6 dead in 6 weeks? This is unacceptable.”

“Oh please you act as if we've done nothing about this. I’ve already sent people to look into it but to no avail.”

“You underestimated the threat, as always.”

“You better not be implying what I think you’re implying.”

“What? That you have dismissed the armed detective agency time and time again leading only to your downfall.”

“Since your little club is so great you won’t mind sparing me a certain someone to work on this little issue.”

“Typical, I suppose you will offer up an equal counterpart to use to manipulate your way into a truce, long enough for us to draw our attention away from you and your mafia.”

“Fukazawa you wound me, surely you don’t think this stunt isn’t just bothering your agency. The port mafia has important inventory in France and I’d rather like for the attention to shift away before our presence there is discovered.”

“And if I refuse? Surely it would be in my best interest for this inventory to be discovered.”

“Then the bodies will continue to pile up with no end in sight, this deranged individual will kill and kill till he gets bored and moves to a new location to turn into his personal graveyard. I understand your hesitance but I will play my trump card if you play yours. We will either both win in the end or lose. 50/50. Whaddya say?”

“Mori don’t pretend like this decision is in my hands, you know the answer because you know I have no choice.”

“Splendid, see you Monday.”

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“Surely we can’t start the meeting yet, the president said it was important and Dazai isn’t here yet.” Atsushi asked, eyes flickering from the members already sitting to the door that had been untouched for the last 20 minutes.

“That’s never stopped us before.”

“Don’t say that Kyouka.” Atsushi pouted lightly, going through the motions.

“She’s not wrong, that lazy bastard will either be half an hour late or never show.”

The entirety of this interaction felt like déjà vu, unfortunately for everyone Dazai was rarely punctual, although there was a higher chance of him showing up when they weren’t already informed about what the meeting would be about. Some say it’s because he's curious but it’s more like he can't already have everything figured out if he doesn’t know what it is, and that bothered him. Curiosity may have killed the cat but if the cat had just been three steps ahead his nine lives would be intact.

“No worries, Dazai and our guests will both be here shortly, knowing the timings Dazai works to he may just run into them on his way here. We’ll begin.”

The agency fell silent at the presidents’ words, Kunikida still squirming slightly in his seat, enraged once again at Dazai’s tardiness and blatant disrespect that even the president had noticed.

“We have been given intel regarding a string of murders taking place in Monte Carlo France. It has been 6 weeks since the first murder and since then there has been a new victim every week. As you can believe this is a worryingly short amount of time between murders and the French lack resources capable to counter ability users.”

“What has led them to believe it is an ability user?”

“Simple, the complete lack of any evidence. No point of entry, no exit, almost no struggle, no murder weapons, no witnesses and no survivors. Even worse these murders are all happening within one area and even with the sheer number of guards being stationed there is no sign of them catching him anytime-” The president was cut short by the approaching sound of two people's voices.

“Oi bastard that’s my foot you're standing on.”

“My condolences, I couldn’t see you from down there shorty.” The voices were growing louder the closer they got causing heads to turn towards the large door that acts as the only entry to the meeting room.

“After 7 years you’re still using short jokes, I think it's about time you reboot your creativity it's getting old.”

“Whatever you say, you compressed ball of anger.”

Before the first man could reply the doors to the office were flung open by those who were previously bickering, each shoving the other as they desperately competed to get through the door first. The president sighed, resting a hand to his forehead as the boys finally stumbled forwards, making it a draw. It was obvious that Kunikida was doing everything in his power not to shout at Dazai, he would’ve, if it weren’t for the unexpected guests that joined him.

“Yosano, please remind me that I need to get these walls fitted with soundproof material.” The president said with no sign of sarcasm.

“Don’t tell me you started without us Fukuzawa, after all we were the ones who asked for your help with this.” Mori cooed making his own way into the room, rightfully letting the boys shove their way through before getting too close.

“President please do explain, I cannot express the sheer need to kill myself when I ran into this dwarf at the buildings entrance.” Dazai wined swinging his arms widely clearly trying to stage an accidental smack to Chuuya’s face.

The now even angrier looking executive shoved Dazai away before a limb could connect. “Tch you're so dramatic go take your seat like the good little employee of the agency you pretend to be.”

The president cleared his throat wordlessly signaling to both the agency and the port mafia to just get straight to the point.

“As I was saying,” he continued while Dazai joined Atsushi and the mafia sat on the opposite side of the table.

Mori deliberately swooping into the chair Chuuya was approaching at the last second, forcing him to sit opposite Dazai, that man loved to bring misery to anyone he could. He considered just sitting on the floor or floating at the other end of the table but decided against it as to get this mysterious meeting over with. he resisted the urge to throw up when Dazai winked his way.

“The mafia was contacted after the third murder and they allowed 3 more to happen before coming to us.”

“We sent what we thought was a sufficient amount of men but we either heard nothing from them having to report them as MIA or came back with no leads.”

“Resorting in them finally requesting our help.”

“Ok so when do we leave, if we all go, we can just flush out the bastard and call this a day.”

“Not quite, as I stated before the mafia arrived, it is believed that this person has an ability that allow them to move around completely unnoticed, potentially teleportation or invisibility. Due to this if they were to be scared off by a conspicuous man hunt it’d be impossible for us to find him before he manages to escape.”

“I can confirm it's not invisibility, we had our men set up cameras in main areas searching for heat signatures and comparing that to a normal camera. We found nothing meaning that the ability must be something else, it makes it easy for him to enter, surprise, subdue, kill and exit.”

“Fuckin fantastic.”

“Quite.”

“Alright then stop tiptoeing around the subject, what are we doing about this? You’ve clearly come up with something, out with it.”

“Now now Chuuya if I were you, I wouldn’t be in such a rush to find out.”

“Fuckin fantastic.”

“Due to the nature of this situation, we have decided that this will be an undercover mission, the chosen candidates will pose as tourists and gather intel without being detected. They will travel to the south east coast of France under a well thought out cover story, spending a few weeks to compile a list of suspects and better yet arresting the culprit before anyone else is killed.”

“But president sir ya already said that this person has gone completely unnoticed but is extremely dangerous. Who are ya gonna pick? Ranpo would be an obvious answer but he – no offence Ranpo – can't exactly defend himself.” Kenji piped up.

“Plus, he’d get lost before even getting on the train.” Yosano laughed, “That is if it is a train, God a plane would be even worse. He’d somehow end up in Florida or Egypt.” Yosano continued to chuckle as Ranpo waved an offended lollypop in her direction.

“You may jest but that was a legitimate point to look at when deciding the members who would be going. We decided that as the ada and pm are working on this together it's only fair to have the same amount of people going from each group but touching on the point from earlier it's imperative that no attention is drawn to your presence. So with that we've decided on one member from each group.”

Kunikida warily spoke up “Seems like far too little, how are two random members from opposing groups supposed to work together?”

At this Dazai practically leapt out of his chair, heading rigidly but quickly towards the door at the opposite side of the room. Ranpo chuckling in that wise but know it all way he does and grabbed the end of Dazais’ coat as he passed by his chair. At the small amount of resistance Dazai gave up his attempts at escape but made it very obvious from his face that he was not happy.

“I know where this is going.”

“Oh I’m sure you do,” Ranpo giggled, this scene being even funnier to the young male as he was faced by extremely confused faces from almost everyone else in the room.

“Of course those two have figured it out but would anyone care to fill the rest of us in.”

“we understood that we needed two members that can work together while also having the ability to figure out the case and stay safe. Those with the highest success rate are Dazai and Chuuya.”

Silence eloped the room as the news sunk in.

It didn’t last long.

“WHAT?” Chuuya bellowed he too now flinging up from his chair. This had been the first time he’d spoken all meeting, he tries to remain as professional as possible in meeting only being achieved by him not talking, but now that all goes out the window.

“Oh boy here we go.”

“Are you takin the piss, I haven’t worked with this bastard for 3 years and you now expect me to spend weeks in FRANCE looking after this fool and solving a case that has so far stumped an entire country.”

“For once I agree with the shrimp, how can I get anything done while tripping over this flamboyant eyesore.”

“Now now boys think about it, who would you rather we send. You can't deny that you are the only ones here who have ever really worked together.”

“Send Akutagawa and the tiger then.” Second of silence, “Wait no never mind that would be a shit show.” Atsushi and Akutagawa both furiously nodded their heads in agreement from opposite ends of the table.

Mori was practically giggling like a school girl in his seat.

“Cut that out Mori, help.”

“I can't help it, this is already fantastic and they haven’t even heard the best part.”

“Ey farm boy I’m gonna need you to clobber me over the head till I die.”

“Well sure Mr fancy hat but I'd only need to hit you once, what would you like me to do it with?”

Chuuya cocked an eyebrow at Yosano who shook her head, having a silent conversation discussing Kenji’s lack of understanding sarcasm.

“How about we discuss the specifics of this case before going any further with the plan. Boys if you will,” Fukuzawa continued gesturing to the two empty seats both boys begrudgingly sat back down in.

Everyone’s eyes were on both the president and the boss, the room dimmed like the mood as the blinds where closed, the projector lit only everyone’s facial features, a sea of sorrow staring up at a picture of a hotel. A very luxurious one at that.

“On the 14th of March we received a call from the French police, explaining how there had been 3 murders in the last 3 weeks, asking if we could send assistance as so far they had found nothing and assumed it was an ability user. It was decided that we’d send a team of 10 as the timeframe to victims was only a week. At first the police couldn’t figure out how the cases were linked besides their location, all three murders had happened either inside or around the luxury hotel Hermitage. The men we sent took pictures and made detailed reports of each crime scene and sent the information back to be worked on. Clearly they made their investigation far too obvious as our men started to disappear and then one became the fourth victim, spooking the remaining subordinates to pack up and come home. But before that, they discovered that in each crime scene there was a precious gem hidden in his ‘art?’, the files sent back included images.” Mori detailed.

“At first they thought that there was a drug cartel or some sort of organisation. Which is why they originally reached out to the port mafia, due to their unconventional practice they thought they may be aware of potential rivals in different countries.”

“Why? I thought there was no evidence that led to a culprit, let alone suggest a large group of people like a gang.”

“Here are a couple of pictures from the crime scene.” Mori stated bluntly, as if they would answer that question.

“Mori no-” but Fukazawa failed to stop him before he shared an image on the projector.

At the sight of the enlarged picture, while most turned to face it some got one look and quickly snapped their heads in the opposite direction.

Atsushi with his eyes looking anywhere but the gruesome scene before him watched as Akutagawa mouthed pussy his way, all he could do was put up his middle finger as there was no way he would prove a point and look back at that horrific crime scene plastered against the wall.

It was evident that this used to be a prestigious hotel room but now all that remained was blood-stained surfaces and a very disfigured corpse. Bones visible but not connected to each other how they’re supposed to be. It looked like a totem pole of flesh and joints with a skull placed on top, hands on the floor somehow holding up the severed skin of a female face, makeup scattered in the background, crudely having been smeared on the flappy skin of what remained of her face. A small shining stone placed on the middle of the collar bones that the skull wore as a crown.

“As you can see, this has become a big problem.”

“But this isn’t us trying to force you boys into accepting this mission, this is a very serious matter, your lives will be in danger and you have every right to decline. But do know that it will be done legally, with you working closely but secretly with local police. And at any sign of your covers being blown we will have you back in London by the hour.”

Silence fell over the whole room, some still studying the disturbing crime scene while others studied the opposite empty wall. The oldest men were waiting for an answer from only a fraction of the people in the room but it was like everyone was making up their own mind on what to do.

“Why not send me? Why does it have to be Dazai.”

“This isn’t a trust thing Kunikida it's just that Dazai is the most suited to figuring this out.”

"you act as if I'm not a detective."

“Sure lets send you off into a den of pricks that likely used illegal methods to gain their wealth and let you wave your notebook around like a target board, shouting about morals and justice. I'm sorry Kunikida but I agree, Dazai has a track record of figuring things out being second only to Ranpo. Besides, are you going to work closely with Chuuya or any of the port mafia members without blowing a fuse. Actually Chuuya will you be able to?” Yosano pondered aloud not expecting an answer to her last question more just airing that concern to the group, showing no fear for Kunikida or Chuuya speaking freely and matter-of-factly.

Yikes this is awkward. Dazai thought, glancing over at Chuuya who was also grimacing at the bickering that he was clearly trying to stay out of. Knowing him he too was trying to place the puzzle pieces together and figuring out whether this is doable and if not who to take their place.

“I could go with Akutagawa.” Kunikida said through clenched teeth, he himself clearly despising the idea.

“Akutagawa’s banned from entering French soil, he wouldn’t make it past security.”

“Obviously, whatever just don't come crying to me when Dazai goofs off and ends up dead.”

There was a silence that filled both room and mind, everyone in the room simultaneously had second thoughts over this assignment. Who would be better? Maybe the president himself? Or send Ranpo with Chuuya or even go and find Poe. Where was Tachihara, could he replace Chuuya? However, this silence was soon broken once again.

“Soooooo, are we riding first class?”

All eyes turned to the once quiet Chuuya.

“What are you talking about Chuuya?”

“Eh, I’ve never been to Monte Carlo, might as well make the most of it.” He shrugged as if this were the most pressing matter out of everything they’d just been told.

“So, you’re accepting the proposal?”

“Eh think of it as me accepting an all-expenses paid holiday to be a bit nosy. I'm expecting spending money.”

“Well, that’s one way to look at it.” The president gave a small smile at the childlike view of the situation, appreciating what he thought to be Chuuya’s attempt to stay optimistic.

“God Chu you're so stupid.”

“Oi”

“In that case I suppose I’m in as well. I’ve gotta help this idiot stay inconspicuous and stop him from punching everyone who looks at him funny.”

“OI. At least I'm not the one who needs to be babied, you'd be dead in an hour without me.”

“you're right and that is why we chose you two. Now that’s sorted we’ll continue this later, I expect both of you to be here at 7 am tomorrow,” Fukazawa detailed looking directly at Dazai when specifying the time, “to go through the evidence already collected and go into more detail about your undercover identities. For now you are all dismissed.”

“I need to discuss a quick matter with Fukazawa you lot hang around,” Mori ordered.

Just great, Chuuya thought, he had wanted to escape as quick as possible and scream on a roof top somewhere. The agency members walked back to their assigned desks like muscle memory. Apart from Atsushi who was tripped up by Akutagawa and had to hang back for a second to punch him in the arm.

Chuuya felt like a lost dog wanting nothing more than to leave the building but felt like he'd be scolded by Mori later, so instead he hovered around. First walking past Ranpo who hurriedly scooped up his immense pile of sugary snacks, as if Chuuya was about to lung at them. Next was past where Atsushi sat, the boy instantly straightening up in his seat and becoming very rigid, putting so much thought into looking professional that he stopped actually doing anything, his work forgotten. He next passed Kiyoko who he was originally planning to ignore until he noticed her also tense up and caught a quick daunting look flash across her face. Surely she had to know that her leaving didn’t bother him after all he was already used to it, so to silently convey his lack of anger he ruffled her hair ever so slightly while moving past swiftly, pretending not to notice her small relieved smile.

Unfortunately, he next found himself at Dazais' desk, a mess littered with random paper, trash and stationary, none of which looking work related. The man had been watching him walk, he knew it, probably trying to psychoanalyse him, not that itd work, he'd play naive and present like a blank slate, like none of this shit bothered him.

Dazai was laying back in his chair, his feet ever so slightly perched on the edge of his desk, like that would save him from Kunikida shouting at him. He would’ve if the man weren’t furiously working on the next desk.

“Someone call Willy Wonker, one of the Oompa Loompas have escaped.” This remark earned the man a swift upward kick to his precariously poised legs, just enough to cause him to fling forward in his chair as his legs fell back to the ground. Chuuya huffed a noiseless laugh as he perched where Dazais legs had just been as it was seemingly the only part of the desk that had space.

He looked down at Dazai, a rare thing but he had the height advantage of the desk compared to his chair. “What’s with you.” He asked nonchalantly, not a question more a statement but still he asked it quietly as to not be seen talking to Dazai. Picking up a piece of paper besides him as Dazai rolled his chair next to him, he was now sitting at his desk next to where Chuuya lent.

“Nothing.”

“Uh huh that’s why you're unusually quiet. Nothing.”

Moments like this weren’t unusual, that was 7 years ago but now it felt like a fever dream, a deadly secret.

They both busied themselves with watching Akutagawa lean over Atsushi to point out every mistake in his paperwork while he tried to elbow him out the way. Chuuya noticed Gin standing nearby usually very protective of her brother even if it were hidden well, but now he could be wrong as she was wearing her mask but he was almost sure she was smiling.

Oh to be that age again.

He found his eyes trailing back to Dazai, meeting his.

“I'm sure it'll be fine.”

“I almost threw up looking at that image.”

“Oh wow the stoic and tough executive Chuuya Nakahara was almost sick because of a little blood. Surely you of all people should remember the crime scenes we used to leave.”

Kunikida looked up at this comment, he was still after all this time, struggling to comprehend the fact that Dazai was mafia.

“The worrying part is that after doing all that shit with the body he must’ve been covered head to toe in blood, how does a man looking like that go completely unnoticed?”

“That’s what we’re going to find out.”

“That’s if you both don’t die.”

“Thanks Akutagawa.” Chuuya rolled his eyes as Akutagawa seemed to ponder what he just said.

“You're both definitely going to die.”

Everyone turned to look at them after that very blunt statement.

“Can I keep your motorbike?”