Archive of Our Own

“So, are you going to help me solve it or what?” 

Minamoto Kou has experienced his fair share of odd clients in his time working as a private detective. Sure, his brother- genius detective Minamoto Teru, who has been solving cases with ease and grace from the moment he set foot out of the university grounds- always gets to tackle the more serious cases. But Kou definitely oversees the more interesting investigations- stolen greenhouses, veritable graffiti masterpieces showing up on people’s walls overnight, even a crop circle one time- he’s seen it all. 

And now, on the fifth floor of a run-down apartment block- there’s a ghost with bright pink hair and an unimpressed look on his face, floating right in front of Kou like something out of a special effects show. Had he not experienced the paranormal before, long-dead pets curling up at the foot of his bed when he was a child, the miserable ghost who used to kick in the doors of the university toilets, Kou would have dismissed it as some elaborate practical joke.

“Are you gonna help, or are you just gonna stare at me, you creep. ” Kou watches in nothing short of amazement, as the ghost prepares to kick him, and swings his foot straight through Kou’s leg.

The day goes on, Kou overcomes his initial confusion, and as the midday traffic sweeps by on the street outside, Kou finds out the following: 

The ghost’s name is Mitsuba Sousuke, he is ( was ) a photography student, and, most importantly, he was murdered. 

 “Could you try and look a little less excited about it, lame-earring detective.” Mitsuba pouts, as Kou feels his face light up at the mention of a murder case. Such jobs are normally Teru’s battleground, left to the expert eye of a senior detective with years of solved mysteries under his belt. Meanwhile, Kou is normally relegated to petty thefts and household disputes.

He knows he’s not as good as his brother, that he has a lot left to learn- but that doesn’t mean he’s got nothing to prove.

If Mitsuba Sousuke wants Kou to solve his murder- then he’s going to meet the challenge with everything he’s got.

“Sorry, I just don’t normally get these kinds of cases. I’m excited to get to do some real detective work here!” Kou responds, though he at least makes an effort to school his grin into something more like an understanding smile, not wanting to offend his client. 

“So you’re not just a detective creep with a lame earring- you’re a subpar detective creep with a lame earring,” Mitsuba throws himself backwards to float an inch above one of the armchairs, the lurid pattern of the fabric just about visible through the slight transparency of his clothes and skin. “I’m doomed.”

“Don’t you worry, Mitsuba,” Kou beams, because while he may not be the most experienced of detectives, he’s nothing if not enthusiastic, always ready to take on a new challenge. “I’ll solve this case with everything I’ve got, and then you can move on peacefully!” 

Mitsuba unfurls himself from his position above the armchair, and stares. He looks at Kou like he can’t quite believe his eyes- like Kou is the otherworldly apparition here, not himself- and Kou shifts under the weight of his gaze. Then, be it minutes, hours, days later, Mitsuba blinks.

“I suppose, if you’re all I’ve got.” He scoffs, same as usual, and Kou wonders if he imagined the look Mitsuba was giving him in the first place.

-

Kou knows, in theory, how the investigation process goes. He’s accompanied Teru on enough cases to know this particular drill off by heart. However the process of collecting evidence with a ghost floating less than a meter behind him, making snide comments about his technique, his clothing choices, how he can’t go in certain cupboards because he’s still using them as a makeshift dark-room- it complicates things, to say the least. 

“Can you water my plants while you’re at it?” Mitsuba asks, floating somewhere near the kitchen table as Kou tries to maneuver around him to swab the chairs for fingerprints. Kou thinks he might just scream.

He fills up the tiny yellow watering can by the sink, anyway.

Despite the fact that he gets in the way of every one of Kou’s investigation techniques, Mitsuba is surprisingly fun to be around. He’s got a terrible attitude, refuses to call Kou by his actual name, and has accused him of being a creep no less than seven times since he stepped into the apartment- but Kou can’t bring himself to dislike him.

He’s entertaining, still so full of life despite the way the light passes clean through him, and the way his feet never touch the floor- so much so that, after a few hours have passed, Kou has begun to forget that he’s speaking with a ghost, and not a normal human.

“Can you tell me anything you remember about the day of the murder?” Kou asks, deciding that his search of the apartment has been thorough enough to move onto the interrogation side of things. He’s not entirely sure what the protocol is for questioning the victim of the murder themself, but spontaineity is something Kou is well versed in, so he launches straight into it. 

Mitsuba looks up from where he’s prodding at the leaves of one of his potted plants. “That’s a little insensitive, isn’t it?” He responds, floating over towards Kou. “Asking a guy as cute as me how he was murdered. ” 

“Mitsuba, this is a murder investigation,” He holds in a sigh, and very heavily doubts that Teru has to deal with this sort of thing on his own cases. “A murder investigation which you called in for.” 

“Well, maybe I just wanted the company, not to be probed about sensitive topics,” Kou lunges across the table, and his hand goes straight through Mitsuba’s arm, cold and unsettling in a way that makes him shudder violently. “Okay, Okay! It was a Friday! About a month ago, I think.”

Kou stares. “A whole month ago? You didn’t think to call in sooner?” 

A cloud passes over the sun outside, cutting off the light that previously poured in through the window. It makes Mitsuba’s form seem a lot more intangible, washed-out and transparent, like the slightest breeze would blow him away. He sighs, heavy and almost overwhelmingly sad, and Kou kind of wishes he could touch him- so he could offer any form of comfort.

“It was difficult, okay,” Mitsuba speaks in a subdued voice, none of his previous boisterous tone and insults on display. “I called every detective agency I could, but none of them could hear me. You were the only one.” 

It strikes Kou, then and there, just how lonely it must have been.

Kou has never known a time where he’s not been surrounded by people. Be it his siblings, his friends, people he’s helped in the past who still smile at him when he passes by on the street- he’s always been a person who thrives around others. And here in front of him stands Mitsuba, who has been alone for months- who has none of the warmth and company that Kou makes a habit of surrounding himself with. 

The sun is still buried behind the clouds, and Kou feels awful. 

“You’ve got me now, though!” He announces, standing up from the table with a blinding grin, one which seems to knock Mitsuba off his guard. “I’ll solve this mystery, and keep you company while I’m at it.”

An odd look passes over Mitsuba’s face, one which Kou can’t quite recognise, but it’s gone fast enough for him to wonder if he imagined it. In its place sits his previous smirk, his terrible attitude back in full force, and Kou is surprised to find that he almost missed it.

“So the lame-earring detective creep is so desperate for friends that he’ll settle for dead people?” Mitsuba jeers, floating a good few inches off the ground. 

Still, Kou doesn’t even regret his promise one bit.

-

Kou comes back to the apartment the next day, bright and early. He lets himself in with the key Mitsuba gave to him after claiming that he no longer needs it, due to his recently developed ability to float through walls. However, no sooner than he’s stepped through the door, he finds a plastic plant pot sailing through the air towards his head, and he makes a mental note that early starts are less than appreciated. 

“I’m trying to get my beauty sleep, lame-earring detective!” Mitsuba shouts, armed with an entire stack of empty plant pots. Kou closes the door behind him, issuing a sheepish apology as he does so. 

“If you can interact with objects, then why didn’t you just water your own plants yesterday?” Kou asks as he pulls out the apartment floorplan he managed to download, thanks to a quick visit to some estate agent websites. From somewhere behind him, Mitsuba splutters, and drops his stack of unused pots on the floor.

“You weren’t doing anything else productive- I was keeping you busy,” Mitsuba eventually quips, then moves to float over Kou’s shoulder. “Looks boring.” 

“I’m adding the evidence I found to a floorplan of your apartment. I looked over all the samples I took yesterday, so the next step is to organise my findings. I think.” Kou explains, trying not to flinch at the way Mitsuba’s presence behind him is almost cold enough to make him shiver.

“You went over all that stuff already?” Mitsuba sounds almost impressed, if not a little horrified, and Kou takes it as a small victory.

“I probably didn’t sleep as much as I should have last night,” He explains, looking a little guilty. He feels like a hypocrite, in all honesty- always reminding Teru not to stay up all night working on cases, then doing the same himself. “I wanted to get all this done as soon as possible, though.”

“So, did you find anything?” Mitsuba asks, and though it might just be his imagination, Kou thinks he sounds somewhat worried. 

“Pretty much all the fingerprints were the same, so I’m assuming they’re yours. There was some dirt on the windowsill, which might suggest someone disturbing the plants by entering through the window, but there was no other evidence of someone climbing in. Other than that, nothing,” Kou sighs. “Normally you’d expect to find blood, or signs of a struggle, but everything looked normal.”

“Well- maybe they were just very efficient.” Mitsuba proposes, not quite meeting Kou’s eyes.

“Are you sure you don’t remember anything about what happened?” Kou pushes, while Mitsuba’s guards appear to be down. “Not a single thing?” 

“I-” Mitsuba hesitates, and Kou immediately feels bad for asking. As much as he’s desperate to solve the case, for both his and Mitsuba’s sakes- he should know that impatience won’t cause anything but trouble. “I really don’t.” 

“Don’t worry about it too much,” Kou plasters on a smile, hoping it comes across as genuine. “I said I’d solve this case for you- and a Minamoto never goes back on his promises!” 

Mitsuba rolls his eyes, and if he’s not mistaken, Kou could almost say the gesture seems fond.

-

A trip to the small coffee shop down the road, upon Mitsuba’s recommendation, tells Kou that Mitsuba can in fact leave the perimeters of his own apartment. He floats right behind Kou as he walks down the street, making comments which Kou can only respond to when he’s sure there’s no passers-by in earshot. 

They settle towards the back, choosing a booth near the sound system in the hopes that the jazzy instrumentals will drown out any sign of Kou talking to himself. He orders the strongest coffee he can spot on the menu, wrinkling up his nose at his own choices before dumping in an excessive amount of sugar for good measure. 

“If you have a heart attack from drinking that, then we can haunt the coffee shop together.” Mitsuba proposes, glancing from the cup in Kou’s hand, to the regret he knows must be written clearly across his face. Kou has never been partial to bitter tastes, but he needs to be alert if he wants to solve this case well, so the hit of caffeine is something he needs, regardless of how bad it tastes. 

He takes a sip, grimaces, and Mitsuba laughs so hard he almost falls through the cafe wall. 

-

“Something’s been keeping you busy.” Teru comments, coming home from work to find Kou huddled over his floor plan and his laptop, line of sight jumping between the two like he isn’t sure where to start.

“I got a case,” Kou looks up, excited to finally let Teru onto the secret. “A proper murder case- no missing cats or stolen vegetables in sight!” The surprise on Teru’s face is almost palpable, and Kou wonders if it would kill him to look a little more impressed.

“Who’s the client?” Teru asks, skimming over Kou’s notes with a satisfied nod, a simple gesture of approval which makes a feeling of pride bloom in Kou’s chest.

“It’s uh,” Kou fidgets in his seat. “The victim.” 

Teru freezes. “Kou-”

“I know, Nii-chan- ‘ don’t meddle with ghosts, they’re nothing but trouble’, ” He reels off his parents’ words, drilled into the two of them ever since they mentioned seeing their late pet cat, still sunbathing on the stairs weeks after he died. “This one is fine though- he’s called Mitsuba and the worst he’s done is tell me off for overwatering his plants.” 

The look Teru gives him is nothing short of skeptical, and Kou feels disappointment steadily filling his chest like glue- uncomfortable and difficult to breathe through. “I really don’t think you should be-” Teru starts, trailing a finger along the edge of the floorplan, and Kou surprises himself by jolting to his feet, almost knocking his chair over as he goes. 

“Teru-nii, please just trust me for once. I know what I’m doing.” He speaks defiantly across the table, lit by the glow of his laptop screen, to where Teru stands unsettlingly still on the other side. They stare at each other for what feels like hours, the silence falling heavy and uncomfortable between them, until Teru turns and laughs a small, disbelieving laugh.

“When did you grow up so much?” He muses, more to himself than anyone else, then looks up at Kou with a satisfied smile. It’s not pride as such- but it makes Kou feel as though the weight of the world has been lifted from his shoulders regardless. “I’m sure you’ll do your best, Kou.”

And then he’s heading up the stairs without another word, leaving Kou with nothing but the hum of his laptop fan to keep him company.

-

For the next week, Kou works away tirelessly at the case, questioning Mitsuba’s neighbors, consulting all the local news sources he can find, taking evidence around the apartment and drinking excessive amounts of coffee from the cafe down the road. All the while, Mitsuba follows him, never floating more than a few metres away, armed with ten-folds of insults and shrieks about Kou’s creepish nature every time he tries to step into the bedroom to look around. 

He’s almost gotten used to Mitsuba being there- it feels too quiet when there’s not a constant cold presence behind him, making fun of his handwriting then sulking in the corner when Kou cooks lunch in his kitchen, filling the apartment with the smell of spices. Though, for all his complaints, Mitsuba never once tells him to leave, even admitting once that he appreciates Kou’s company, despite his blatant disregard for proper plant care.

Kou thinks he’d go as far as to say that they’ve become close friends.

Kou catches himself learning a lot about Mitsuba too- he finds that he won competitions for his photography when he was younger, that he recently got accepted into an internship at a fashion magazine, that he always wanted a younger sister whose hair he could style. (Kou offers him Tiara, with a warning that she might bite him if he tried.) 

It’s almost enough for Kou to forget that Mitsuba isn’t alive, surprising himself when he goes to tap his shoulder to get his attention, and his hand passes straight through. 

He actively makes an effort to avoid it, when he sees the sad look that passes across Mitsuba’s face. 

Despite all that he now knows about Mitsuba, Kou feels like he’s no closer to solving the case than he was at the start. No matter how hard he looks, he can’t find any leads- none of the neighbours saw anything suspicious, there’s no sign of a struggle around the apartment, and Mitsuba still insists that he doesn’t remember a single thing. It’s like he’s hit a dead end, and Kou finds, despairingly, that he doesn’t know where to look next.

He could ask Teru for advice- but that would feel too much like admitting defeat.

He promised Mitsuba he’d solve this case. And so he must be the one to see it to the end. 

A Minamoto never goes back on his promises, after all.

-

“What do you think you’ll do, once I’ve solved this?” Kou asks, as the sun sinks below the skyline beyond the open apartment window and stains the furniture in shades of gold. The light passes straight through Mitsuba, as he raises his camera and takes photos of the plants in the corner of his living room. 

Mitsuba lowers the lens of his camera- slowly, deliberately. “I don’t know. Move on, I guess.” 

Kou hadn’t really thought about that. 

But Mitsuba is right- he’s probably only still around because of this unfinished business. Once he has his answers, there’ll be no reason for him to stay, no reason for him to subject himself to an afterlife stuck in limbo, with only Kou and his sloppy investigation techniques for company. 

It surprises him though, just how much he doesn’t want to see Mitsuba go. 

“Hey, I-” Mitsuba starts to speak, but Kou stands up sharply, cutting him off before he can say anything that makes him want to be even more selfish. 

“I’ll make sure to solve this case quickly then- so you can move on with no regrets!” He knows the enthusiasm in his voice falls flat, and that Mitsuba can probably see through him as though he were made of glass, but he still puts on the brightest smile he can muster, and hopes it’s enough.

“Thanks, Minamoto.” Mitsuba sighs, speaking Kou’s name for the first time in all the weeks they’ve known each other.

It strikes Kou, then and there, that Mitsuba looks like he doesn’t want to leave either.

-

“Why are you still here, Minamoto.” The sun has long since set below the skyline, but Kou is still desperately searching for leads, looking over every corner of Mitsuba’s apartment. He’s convinced that he’s missed something- that he just needs to find one small clue which will make everything fall into place. Mitsuba floats in the corner, keeping well out of his way and looking more and more unimpressed by the second.

“I’m not done looking- I’ll leave when I’m finished.” Kou responds distractedly, peering under the leaves of the plants by the window. He can feel himself growing increasingly frustrated the longer he goes without finding anything. The knowledge that Teru could have solved this case ten times over in this amount of time hangs over his head like a death sentence, and he refuses to let the weight of it crush him. Not yet, not while Mitsuba is still counting on him. 

“ Minamoto ,” Mitsuba pushes, looking more than a little exasperated. “It’s late. I’m fed up of you interrogating my neighbors and manhandling my plants- go away.” He doesn’t sound annoyed as such, but Kou still sets his face into a frown.

“I need to do this properly- I’ve taken long enough as it is.” Somewhere above his head, the pressure weighing down on him grows a little heavier.

“Why are you so insistent on doing things perfectly now,” Mitsuba bites back. “You’re not fun anymore.”

Kou draws in a heavy breath, and hates the way Mitsuba can probably hear the way it shudders on its way back out. “I need to prove that I can do this,” He replies, into the emptiness of the apartment. “I need to show that I can be just as good as my brother. This my first big case, and I’m already making a mess of it.” 

For a long while, there’s silence- the window too high up to hear the cars passing by below them, and Mitsuba’s presence still enough for Kou to doubt that he’s even still there. Then, quietly-

“Minamoto, there is no case.” Mitsuba says it like he’s finally been defeated, and Kou’s hands freeze around the leaf of the plant he’s holding.

“What do you mean?” He asks, and hates how unsteady his voice sounds.

“I mean, I lied. I wasn’t murdered.” Kou stares across the space between them, and feels distinctly like the floor has crumbled into nothing below his feet. 

If Mitsuba wanted him gone- Kou thinks, as he packs up his things and walks out the front door- then he’s managed it in record timing.

-

Betrayed is a word Kou could possibly use to describe the feeling which curls deep and nauseating in his gut. However, more than he feels betrayed, he just feels confused . 

Confused as to why Mitsuba would lie to him, as to why he would keep Kou around despite not having a reason to, as to why he’s still on earth, despite not having any unanswered questions to hold him back.

(Most of all, he’s confused as to why he left, without giving Mitsuba the chance to explain himself.)

-

Someone is throwing rocks at Kou’s window. 

It’s the first night since he took on Mitsuba’s case that he’s made it to bed at a decent time, so the sudden disturbance is less than appreciated. But then he glances out of the window to spot Mitsuba, floating above the pavement outside with a handful of gravel from the next garden along, and he’s not sure whether to feel surprised or relieved. 

“Why didn’t you just come in through the door, instead of trying to break the glass?” Kou hisses down at him, after shouldering the window open and hoping that nobody in the street can hear him. Mitsuba frowns, the cracks in the pavement visible through his near-transparent shoes.

“I tried- your whole house is covered top to bottom in anti-spirit charms,” Mitsuba shouts back, depositing his handful of gravel onto the ground. “I understand if you’re angry at me, but don’t you think that’s a bit excessive?” 

“I-” There are times when Kou appreciates Teru’s cautious nature- but this is certinately not one of them. “I’m coming down. Don’t go anywhere” 

He’d be lying if he was to tell himself he hadn’t missed Mitsuba, as he pulls on his shoes and a coat and heads quietly down the staircase, because he knows for a fact that Teru will still be awake. Beyond the front gate, Mitsuba stands in a way that makes him look all too small, like he suddenly regrets his decision, and Kou smiles weakly in the hopes that it'll do something to ease the tension. 

“Can we go back to my apartment?” Mitsuba asks, glancing off down the road. “I don’t want to explain everything out here.” 

And so they walk through the empty streets, car headlights sweep clean through Mitsuba, and the sky fills with clouds like it’s about to start raining. Kou pulls his hood up preemptively, and Mitsuba doesn’t even make an effort to poke fun at him for it. 

“I lied.” Mitsuba tells him, as Kou finally closes the door behind him and they stand, face to face in the moonlit apartment. The tap in the corner is dripping steadily into the sink, and Kou wonders if he can put off the conversation by offering to fix it. 

“I know.” Kou responds instead, because for all his downfalls, at least he’s always been one to face things head-on. 

“I fell out of the upstairs window,” Mitsuba says, as though he were announcing something as tedious as the weather report. “That’s it. No murderers or anything- I was just stupid and clumsy, and I leaned out too far while I was trying to take a picture of the birds nesting on the roof.”

“The dirt on the windowsill-” Kou starts, and Mitsuba nods.

“I took a few of my plants down with me. They were some of my favourites,” He laughs, bitter and humourless. “I lied because I was lonely and I couldn’t think of any other way to get someone to stick around. It wasn’t supposed to go on for as long as it did, I swear- but then you got so invested and I couldn’t bring myself to-”

“Why haven’t you moved on yet, if that’s the case?” Kou asks, because the question has been eating away at him from the moment Mitsuba started talking. 

“Because there’s a whole world full of things I didn’t get to see or do,” Mitsuba admits, staring straight at Kou. “How can I move on, when I’d be leaving so much behind?” 

Before he can even think it through, Kou steps closer- once, twice, three times- until he can see Mitsuba clearly in the light of the moon shining through the window. Outside, it finally starts to rain.

“What can I do to help?” He asks, like it’s the simplest thing in the world- and really, it is . After all- helping Mitsuba is what he agreed to do from the very start. 

Mitsuba stares at him like the world has been flipped on its axis. “Even after I lied to you?” 

“I’m still a little angry,” Kou admits, but still smiles, as genuine and bright as he can make it. “But I told you- a Minamoto doesn’t go back on his promises.” 

“Some company would be nice, then.” Is all Mitsuba requests, finally wearing his usual grin- a little antagonistic, a little teasing, and a lot more familiar than Kou ever imagined it could have become. And though he might be a bit of a useless detective- Kou thinks he can manage keeping Mitsuba company just fine.

- 

“Take me out for coffee.” Mitsuba demands weeks later, floating right above Kou’s head as he sits in the kitchen of the apartment and types up the report for his most recent case- an intense dispute between two neighbors over who kept digging up their allotments in the middle of the night. (The answer was neither, Kou quickly found, discovering the culprit to be a family of racoons living nearby.) 

Kou looks up from the document on his screen. “We go for coffee pretty much every other day.” He replies, more than a little confused. Mitsuba groans, then floats down to lie a couple of inches above the table-top. He pushes Kou’s laptop shut, just slowly enough for him to get his fingers out of the way in time.

“No, I mean, take me out for coffee. Properly.” He puts emphasis on the words, and Kou thanks his detective skills, as everything falls into place.

“Are you telling me to ask you on a date?” Like he’s signing off a jail sentence, Mitsuba nods severely, and Kou thinks he might just fall out of his chair. “But you’re my client, I can’t date you!” He shakes his head- because despite the fact that Kou doesn’t think he could ever go back to a time without Mitsuba floating just over his shoulder- dating a client is one of the biggest taboos in the business. There’s nothing more to it.

“Well, you technically solved my case,” Mitsuba reasons, his grin turning a little too shark-like. “I’m not your client any more.” 

As far as Kou is aware, he’s not wrong.

“So take me out for coffee, Minamoto.” Third time’s the charm, Kou thinks- because this time, he agrees. 

-

Mitsuba can’t actually drink coffee. 

Instead, he goads Kou into buying the sweetest, most expensive drink on the menu, then crams into the booth next to him. He leans in as close to Kou as he can without the risk of disappearing through him, trying to catch the smell of the caramel syrup and whipped cream topping. Then, once he’s had his fill, he leaves Kou to struggle through the act of actually drinking it.

Alongside drinking coffee, there’s a lot of things that Mitsuba can’t do now.

He can’t hold Kou’s hand as they walk down the street, He can’t start conversations in public, for risk of people questioning Kou’s sanity, he can’t go on proper dates to restaurants or arcades or shopping malls. 

He can’t stay around forever. He establishes this early on- one evening, to the sun setting beyond the apartment window and the streetlamps flickering outside, Mitsuba tells Kou that, one day, he will have to move on. That one day, Kou will have to learn to let him go. 

Kou knows this- he’s known it from the very beginning, but it still keeps him up at night more often than he would like to admit. 

Then, back in the apartment, with its growing number of potted plants and its tap that won’t stop dripping, Mitsuba holds up a piece of paper in front of his face, and tells Kou to just hear him out for once.

It’s nothing like kissing a real person, that much is sure. But through the barrier of the paper between them, Mitsuba is tangible for the first time- a little cold and a little uncomfortable, but there all the same. Mitsuba lowers the paper and stares at Kou over the top of it, like his grin isn’t perfectly reflected in his eyes no matter how much he tries to hide it. Through the barrier between them, Kou pokes him in the nose.

Mitsuba can’t go on normal dates. Kou can’t get detective jobs beyond petty household disputes. Still- he doesn’t think he’s ever been happier.

-

“You know, I heard that there’s a house nearby that’s been having ghost troubles,” Mitsuba announces, hanging out in Kou’s bedroom after Kou’s insistence that Teru removes the anti-spirit charms from around the house. (Reluctantly, he had complied, just enough for Mitsuba to be able to make it through the front door.) “Thought they could use your detective abilities to sort it out.”

Kou might not be worth much as a detective- but dealing with ghosts is something he thinks he’s getting pretty good at.

And so he grins. 

“Paranormal investigator: Minamoto Kou does have a nice ring to it, doesn’t it?”