Chapter Text
Somewhere past midnight, the world was reduced to the humid, fluorescent-lit microcosm of Professor Agasa’s basement. Even the cicadas outside had surrendered their clamor, leaving a hush so deep it made the ticking of the old barometer seem thunderous. In this submarine quiet, Ai Haibara hunched over a battered steel workbench, her posture reminiscent of a predatory bird—still but suffused with a latent violence, eyes fixed on the prey of a molecular diagram.
The air was dense with the odors of acetone, solder, old electronics, and the faint but unmistakable note of despair. On the counter, clusters of glassware formed islands in a sea of printouts, post-its, and grimy coffee mugs; the only order was that which Ai imposed on her own work area, cleared and scrubbed at intervals corresponding less to time than to phases of thought. Her hair was tied back haphazardly, copper wisps clinging to her temples where sweat had outwitted her composure. Occasionally, she would pause, a pipette or forceps poised in midair, as if listening for a voice only she could hear. Perhaps it was her own, the one that had been trained to narrate her calculations and cauterize her doubts.
Tonight’s task was the distillation of the self. That was the phrase that came to her, unbidden, as she performed the procedures: not so much chemistry as mortification. For months, she had worked on the antidote as if on an autopsy, dissecting the corpse of her former self—Sherry, the Organization’s prodigy—until all that remained was Ai, the residue of failure and luck. Now, at the endgame, even success felt like a kind of dissection.
She adjusted the flame beneath a retort, the meniscus of liquid inside trembling on the verge of transformation. This was the forty-seventh variant of the formula, if her count was correct. It was probably not correct. Ai had learned to distrust her own sense of chronology; she existed, lately, in an ongoing chemical reaction that consumed her as thoroughly as it produced results. She made notes in an angular, clinical hand, then tossed the scrap into the refuse bin. Her sleeves were dusted with chalk and iodine stains, the cuffs turned back as if in ironic homage to her former laboratory etiquette.
The first indication of dawn was not the light—down here, the sun was a rumor—but the way the air changed. Less oppressively moist, more astringent, as if even the humidity were waking from a bad dream. Ai’s eyes ached from the microscope; she blinked until the filament bulbs in the overhead lamp doubled and then fused back together. On the bench, a tiny ampoule caught the new angle of light and refracted it in a way that seemed almost triumphant.
She was not given to celebration. Not as herself, and certainly not as the sum of the people she had been. Instead, Ai allowed herself the smallest intake of breath, the kind that would go unnoticed by anyone but herself. The solution in the ampoule was limpid, colorless, and almost serene. There was an elegance to it that did not belong to her, or to the Organization, or even to the Professor; it was the elegance of inevitability.
It was as perfect as she was going to make it.
Ai reset the ampoule into its holder and swiveled in her seat, stretching muscles that had not been granted leave for several hours. She considered, for a moment, just staying like this: the work finished, the world unchanged. But even her most elaborate self-deceptions wore thin under scrutiny.
She retrieved the old flip phone from the breast pocket of her lab coat, absently thumbing the casing until her fingerprints became visible in the dimness. There was only one number saved under "Kudo," a relic of an era when anonymity had been measured in technological indirection. She dialed.
The phone rang twice before it was answered.
“It’s finished.” Ai said.
A beat. Then, “Are you sure?” His voice, still in that improbable register—the forced alto of a child layered over the cocksure undertone of a detective. “No risk of another—”
“I said it’s finished,” Ai cut him off. The words were sharper than intended, but she let them stand. “If you want to revert, this is your last best chance.”
“Understood. I’ll come by after school.” Conan said with a faint breath.
“Don’t bother with the act, Kudo-kun. It’s over.” She almost smiled, but caught herself. “No more Organization. No more shadows. If you want your body back, come now.”
The line was quiet, but Ai could almost hear him reconfiguring the world in his head, redistributing the mass of consequences. He would come; he always did. That, at least, was a comfort.
When she hung up, Ai let the phone rest on the table and traced the ampoule’s outline with her finger. The hope she felt was neither luminous nor warm; it was a glacial hope, slow-moving and inexorable, carving its way through the future whether anyone wanted it to or not. She wondered, in a detached way, if Kudo would recognize himself in the mirror when it was all over, or if he would stare and see only the ghost of the person he’d once been.
She thought of her own reflection, then, and of the lives she had folded away like paper birds, tucked into the recesses of memory. It occurred to her that she, too, might have to learn a new face. It occurred to her that, for all the chemistry in the world, there was no antidote for self-recognition.
The first light of morning seeped down the staircase, pale and prying. Ai sealed the ampoule, labeled it in a hand that shook only slightly, and waited.
———
The bell outside the Professor’s gate was half-swallowed by the wet morning air, a plaintive clang that set the house’s structural timbers shivering. Ai heard the second chime from the bottom of the stairwell and did not hurry her ascent. She moved with the deliberate economy of someone who knew that every step, every microgesture, was now a countdown.
The upper rooms were silent except for the low growl of Agasa’s ancient refrigerator and the intermittent chirps of the smoke detector, whose battery had been left for weeks on the kitchen counter but never replaced. She let herself in, sidestepping the debris of the Professor’s absent-mindedness: open toolkits, a pile of unsorted mail, a stuffed toy with the eyes gnawed off by boredom or maybe a passing dog. At the end of the corridor, she found Conan Edogawa standing just as she’d expected—feet planted, hands in pockets, head slightly bowed in what appeared to be study but was, in fact, camouflage. His shadow stretched across the polished floorboards, doubled in length by the low angle of the overhead lamp.
He had not changed, or rather, he had become even more himself: a contradiction, all youth and premeditation, a body still adjusting to the terms of its own diminishment. His glasses were smudged, his tie askew, as if he had run all the way from wherever children ran at this hour. Ai regarded him with the clinical detachment of a virologist appraising a particularly tenacious microbe.
On the table between them, the ampoule rested in a padded dish, flanked by a pair of tongs and a beaker of distilled water. The arrangement was funereal, the antidote itself gleaming with the cool promise of extinction.
Conan lifted his gaze, blue eyes flickering in the electric twilight. “You did it,” he said, voice steady but threaded with a static charge.
Ai ignored the compliment, if it was one. She extracted the ampoule with tweezers, holding it up so the light caught in its perfect meniscus. “This is the only batch. It’s non-reproducible until I can confirm the effects.”
A faint smile, the Kudo variant: sardonic, almost patronizing. “So you called me here to be your lab rat.”
She shrugged. “You like being first.”
He snorted—a noise halfway between amusement and nostalgia. Ai set the ampoule on the table, careful to orient the label toward him. She wondered, not for the first time, whether he understood how much she envied his clarity, his ability to chase consequences to their logical conclusion and still emerge intact. Ai’s own mind was a house of mirrors, every decision refracted until it became indistinguishable from its opposite.
She waited for him to speak, to press her as he always did for details, for risk assessments, for the secret she would not admit even to herself: that this was not just an experiment, but an atonement.
Instead, he said, “Where’s Agasa Hakase?”
“Sleeping. I told him I’d call if we needed a witness.” She smirked.
Conan’s head tipped, “No. I trust you.” flashing Ai his trademark smile.
Ai almost laughed. Of all the things he could have said, that was the one she was least equipped to answer.
She retrieved a plastic cup from the sideboard, rinsed it twice, then broke the seal on the ampoule with a swift, practiced snap. The liquid poured with the viscosity of memory, pooling in the bottom of the cup with a faint, luminous shimmer. She set it before him, her hand hovering over the rim a moment longer than necessary.
“This should be it,” she said, and the words felt like a line recited from a play she did not believe in. “But remember, it’s still experimental.”
He took the cup without hesitation, tilting it to the light as if to verify the solution’s provenance. “I’ve trusted you this far. Let’s do it.”
Ai watched as he raised the cup. His hands were steady, but his eyes—behind the lenses—betrayed the electric crackle of anticipation, the raw, animal fear that undergirded all true risk. In that instant, Ai saw not the child but the person he had been, the person he wanted to become again. She saw his hope, and, against her own code, allowed herself to feel it too.
As the cup touched his lips, the shadows on the wall seemed to shift, lengthening and twisting into strange, interrogative shapes. Ai wondered, as she always did in these moments, what would be left after the process completed—what strange alloy of memory and biology would emerge, and whether it would have any use for her.
She closed her eyes, not to pray but to calibrate her expectations to zero, the one constant in an equation full of unknowns.
In the dark, Ai counted the seconds, each one a universe of possibility.
Ai watched the boy—her creation, her opposite, her single point of convergence with the rest of humanity—lift the cup and drink. There was no ceremony to it, no dramatic pause; he simply swallowed the contents in one practiced, unhesitating motion, as if taking medicine against the common cold.
For a moment, nothing happened. Ai observed, cataloguing the tension in his jaw, the flick of his tongue against his teeth, the way his eyes narrowed in anticipation. Even when he tried to hide it, Kudo’s shrink body betrayed him: a minute tremor in his hands, the faint whitening of his knuckles around the glass. She wondered if he realized how much of his legend was due to this involuntary transparency.
He set the cup down, looked at her, and for a split second—longer than a blink, shorter than a breath—something flickered between them. It was not gratitude, nor camaraderie, nor even the mutual exhaustion of two people who had spent too many nights outsmarting the endgame. It was recognition, pure and dispassionate: predator to predator, survivor to survivor.
“Should I…” Conan gestured toward the hallway, already rising from his chair. Ai nodded.
“Take the guest room,” she said, voice dry. “It’s not as soundproof, but it’s easier to clean up.” she said with a teasing remark.
He almost smiled, a tic of the lip, then turned and padded away. His steps faded down the corridor, absorbed by the plush rug and the muffled anticipation of old walls.
Ai cleaned up, moving with the mechanical efficiency of someone who had already calculated the odds. She rinsed the cup, returned the tweezers to their case, and catalogued the remaining ampoules—a meaningless gesture, since there would be no need for them if this version succeeded. After a moment’s indecision, she sat on the edge of the couch and stared at the closed door behind which Conan Edogawa, or perhaps Shinichi Kudo, was engaged in a battle with his own biology.
Inside the room, Conan’s world tilted. It started as a faint disorientation, the sort of vertigo that comes from standing up too fast, or from realizing you’ve been holding your breath for longer than you thought possible. Then, with the inevitability of a landslide, the sensation escalated: the walls seemed to ripple, the furniture shuddering in and out of focus, a rushing in his ears like the surf in a conch shell.
He tried to steady himself by focusing on a fixed point—the ticking of the old wall clock, the ragged seam in the wallpaper—but these anchors dissolved into a roiling blur. His muscles tensed and released at random, spasms racing up his limbs and ricocheting through his core. It was not pain, exactly, but a forceful unmaking: every cell in his body was suddenly at odds with the others, a civil war of identity and inertia.
He dropped to his knees, hands scrabbling at the carpet, and willed himself not to cry out. Pride was ridiculous in this context, but it was all he had left. The antidote was ice and fire in his veins, cold and burning and then numb, as if he had been immersed in a glacial river only to be struck by lightning on the way out.
Ai heard the muffled thud from the other side of the door. She stood, debated whether to intervene, then forced herself to remain still. She knew the process; she had mapped it down to the microsecond in rats and monkeys and, once, in herself. There was nothing to do but wait, and hope that the chemistry did not choose this moment to exact a final, poetic revenge.
Conan’s vision collapsed to a tunnel, then to a pinpoint, then to black. Somewhere in the periphery, Ai’s voice came to him, filtered through the thick glass of unconsciousness.
“Don’t fight it,” she said, almost kindly.
He tried to answer, but the words dissolved on his tongue, replaced by the roar of blood in his ears.
And then there was nothing. That was Ai’s quo that her turn was next.
He surfaced from nothingness into a world that was both his and absolutely, fundamentally not his. The first sensation was a metallic taste—coppery, dry—on the inside of his mouth. The second was cold, radiating up from his cheekbone where it pressed against linoleum.
Conan rolled over, but the motion was wrong. His limbs responded with a milky slowness, as if his joints had been reset to a different default. He forced his eyes open, and the colors hurt: the overhead fluorescence sharpened every edge, the room a crueler, more clinical version of itself. He was in the lab again, not the guest room, and at some point he had lost the ability to remember the transition.
He pushed himself up with arms that felt unfamiliar—narrower, the hands delicate, more accustomed to precision than force. His chest was tight, not with fear but with the knowledge of fear: a deep, chronic ache, as if someone had tattooed anxiety into his ribcage.
His brain, ever efficient, began to inventory the evidence. His height relative to the table was off by at least ten centimeters. His field of vision, for the first time in years, was unfiltered by the thick lenses he had grown so used to; the world appeared starker, more unforgiving. When he brushed a lock of hair from his eyes, the strand was copper-red, not the expected black.
He stilled. Everything in his body rebelled against the conclusion that was now, inescapably, forming.
A memory rose up—a memory that was not his: the sound of a gasping breath in a laboratory corridor, the pounding of feet against concrete, the sensation of hands (large, rough, male) grasping at a smaller arm and pulling it back. The memory split and multiplied: rooms without windows, voices speaking in code, the omnipresent fear of being discovered. A face emerged, not his own, not even someone he had ever known—just a composite face, made up of all the predators who had ever haunted Ai Haibara.
He felt a rush of anger, but the anger was not his. It was older, deeper, and laced with something that might once have been hope, if hope could survive this many years underground.
He lurched to his feet and staggered toward the sink. The cold metal shocked his palm, and the image in the polished surface above it shocked him even more. The girl in the reflection was Shiho, not the Ai he was used to. This Ai was stripped of irony, stripped even of composure: her lips parted, her eyes wide, the whites visible all around. She was nakedly afraid, and in that fear Conan saw himself.
He touched his face—her face. The bone structure was finer than his, the skin cooler. He pressed a finger to the bridge of his nose and felt the faintest pressure, the ghost of glasses that were no longer there.
“No,” he whispered, and the voice was wrong. It was a dry, almost musical alto, pitched lower than most girls’, but unmistakably not his own. The panic came in waves, each one sharper than the last. Conan braced himself against the counter, knuckles blanching white, and tried to apply logic.
He closed his eyes and tried to steady his breathing, but the memories intruded again. They were a torrent now: late nights hunched over a microscope, the quiet click of a laptop in an empty house, the stifled sobbing of a child who had learned too early that survival was a synonym for loneliness. Every memory was tinged with the pallor of loss, and yet there was a clarity to them, a sharpness that suggested they were not merely echoes but live currents, still running.
He ran a quick scan of the lab, searching for proof that this was a hallucination, a side effect, a dream. But the evidence was remorseless. His hands were Ai’s adult body, his voice, when he tried it again, was her own—cool and biting, even in fear. The reflection did not yield, no matter what angle he approached from.
He tried to remember the last thing he’d heard before losing consciousness. Ai’s voice, saying: Don’t fight it. Then his surroundings morphed into a familiar room, it was the lab room that Haibara was in before he left to take the antidote in the other room. He stumbled from the sink and headed for the lab door. The hallway outside was empty, the house unnaturally still. For a moment, he thought he was alone—that whatever accident had occurred had erased everything but this single, infinitely repeating moment. But then, from the next room, he heard a gasp: high, unsteady, and edged with a panic that sounded a great deal like his own.
Conan made his way toward the sound, heart pounding in a way that was both familiar and unrecognizable. He found his own body, slumped on the futon, eyes rolling under half-closed lids. The skin was pale, the breathing shallow but regular. For a moment, he was transfixed by the sight of himself, all at once alien and intimate.
He knelt beside the body and reached for its—his—hand. The skin was warm, the pulse thready but present. He squeezed once, gently, and was rewarded by a flutter of the eyelids. The gaze that met his was confused, searching, but undeniably conscious.
Conan felt the words bubbling up, “Interesting,” his new throat rendered before his thoughts.
“What… what the hell?” The words slipped out before he could shape them, arriving in a voice that belonged to her, not him—low, level, with a surgical sharpness that dissected every syllable. The sound was wrong, but what disturbed him more was the undertone, a tremor of panic hidden beneath decades of forced composure.
He stood there, trembling in Ai’s frame, and the emotions that surged through him were alien, immense. Loneliness—an endless, freezing pressure. Guilt, not the simple kind that came from breaking rules or disappointing a parent, but the glacial, slow-burning shame of surviving when others did not. He was used to responsibility, even to fear, but this was different: this was a life lived in perpetual watchfulness, a vigilance so total it erased any possibility of rest.
He squeezed his eyes shut, but that only intensified the onslaught: he could see, as if on a split screen, flashes of two lives. His own, yes, but also hers: being hunted through moonlit corridors, the low thrum of the Organization’s labs, the constant calibration of every gesture to avoid suspicion. A childhood reduced to footnotes and code names, punctuated by the rare, blinding pain of loss.
He tried to separate himself from these feelings, to file them away in the same mental cabinet as every other bit of strange data he had ever encountered. But the sensations persisted, relentless. He had not just inherited Ai’s body, but the ongoing narrative of her existence—her fears, her secrets, the loneliness that pressed in even when the room was full.
From across the lab, a groan. Conan’s own body, the one he should have been in, was stirring. It sat up, bracing itself against the table, and for a moment he was transfixed by the image of his own face—drawn, pallid, sweat beading on the upper lip. The eyes were different, though: a pale, almost indifferent blue instead of the usual stormy black.
The other him—Ai, now in his body—blinked. She reached instinctively for her head, then paused at the strange collision of hand and hair. The realization dawned in her eyes, a microsecond of horror quickly masked by calculation. She flexed her fingers, testing the alien machinery of boyhood, then looked up and met his gaze.
For a moment, neither of them spoke. The world seemed to contract around the axis of their shared confusion. He wanted to laugh, or to scream, or to throw something against the wall and watch it shatter; but instead he just stood there, breathing through a mouth that wasn’t his, seeing the world through eyes that filtered everything in hues of regret.
It was Ai—Conan, now—who broke the silence. Her voice came from his lips, oddly childish but leashed with adult self-control. “Well,” she said, drawing out the syllable as if to sample its taste. “This is far from what I expected.” she said. “The swap, I mean. I had projected a binary outcome, not…this.” Her gaze was clinical, dissecting his every flinch. “But you’re still you, and I’m still me. I think.”
“Except we’re not.” He paused, examining the contours of his—her—own hands, the slight tremor that didn’t belong to him. “I can feel everything. Your memories, your…everything.”
Ai shrugged, a motion that was now oddly unfamiliar, given the size of Conan’s shoulders. “I suppose it’s mutual.” She glanced down at her—his—fingers, turning them over as if expecting a hidden switch. “The mind is an adaptive system. Given time, we’ll adjust.”
He believed her, he wanted to. He had no choice but to.
They were silent again, and the moment stretched. He wondered if there was something they were supposed to say to each other, a script for this particular brand of disaster. But the old protocols—reassure, analyze, solve—were useless here.
Instead, he found himself asking, “Are you all right?”
She looked at him, surprised. “Of course I’m not,” she said, and there was an odd vulnerability in the words. “But I will be.”
He wanted to say the same, to mirror her resolve. But inside, the borrowed heart thudded with a strange, aching cadence.
They faced each other, two strangers in familiar skins, and waited for the world to tilt back into alignment. The seconds ticked by, each one stranger than the last.
———
Across the room, his former body—now inhabited by Ai—paced a slow circuit around the laboratory table. She moved with unfamiliar caution, as though afraid her new limbs would betray her at any moment. Every so often, she would pause, stretching a hand in front of her as if checking its calibration. Conan watched, fascinated, as she toggled between his own old tics and her new, unfamiliar musculature.
He tried to stand, to pace as Ai did, but found his sense of balance off. His legs were too slender, his arms too light. He wondered, with a sudden pang, whether he would ever get used to this body, or if every gesture would always feel like an echo from a parallel life.
He walked to the mirror over the sink, half-dreading, half-compelled by the need to see. The girl reflected back at him was unmistakable: Ai’s face, but not the composed mask she wore in public. This was the face of shock, of curiosity, of a child waking from a long, dreamless sleep. He touched the glass, half-expecting it to ripple and admit him back to his old self.
Behind him, Ai stopped pacing. “I take it you’re not enjoying the experience,” she said, voice flat.
He turned, hugging himself tighter. “It’s not that,” he said, and was surprised to find it was true. “It’s just… overwhelming. Everything is different. I can’t even think straight.”
She nodded, eyes narrowed in analytic sympathy. “The mind is a creature of habit. Disrupt the baseline, and it needs time to rebuild the self-model.”
He considered this, then smiled, grim and crooked. “You sound like the Professor.”
A flicker of amusement crossed Ai’s—his—face. “You think I don’t know that?” She ran a hand through her hair, then stopped, startled by the unfamiliar sensation. “I suppose I’ll need to cut this soon. Or find a way to gel it back.”
Conan’s laughter, when it came, was abrupt and a little hysterical. “You look good,” he said, and the phrase sank in, feeling heavier than it should have. “You look… normal.”
Ai blinked blankly in shock, catching on something that she never thought of but quickly regained her composure. “what a narcissist.”
They both went silent.
Conan, to ease the awkwardness started to wander around the room, touching everything—pens, glassware, even the cold metal of the cabinet—just to verify the reality of sensation. With every movement, Ai’s body responded with its own suite of instincts: a habit of ducking away from sudden noises, a tendency to scan corners for threats, a primness about personal space. He realized, with a fresh shock, that these were not just psychological overlays, but deeply embedded survival routines. She had lived every day as a potential victim, and now, so would he.
“How do you manage?” he broke the silence, voicing the question that had haunted him since waking. “How do you carry all that, and still act like nothing’s wrong?”
She was quiet for a long moment. “You don’t carry it,” she said at last. “You just try to stay ahead of it. It’s like running from a shadow. The moment you stop, it catches you.”
He nodded, feeling the truth of it settle somewhere deep in his borrowed chest.
They spent the next hour cataloguing the consequences. Ai led the process, running simple diagnostic tests on motor function, sensory processing, even reaction times. She documented everything, her handwriting—now Conan’s—angular and precise. The irony was not lost on either of them.
Conan, for his part, tried to isolate what was “him” and what was “her.” It was a losing battle. The longer he stayed in Ai’s body, the more he saw the world as she did: wary, analytical, constantly assessing risk. Even his thoughts began to run along her old channels, looping back to memories that weren’t his, arguments he’d never had, regrets that didn’t belong to him. He began to understand why Ai had always kept her distance from the others. Why she had never trusted hope, or comfort, or happy endings.
After a while, they moved to the living room. It was dusk now, the light through the windows filtered to a soft, orange haze. Conan collapsed into the armchair, his new frame barely making a dent in the upholstery. Ai remained standing, leaning against the doorframe, arms crossed—an old pose, made new by the body that wore it.
“So,” Conan said, “what now?”
Ai tilted her head, a calculating glint in her—his—eyes. “First, we determine whether the effect is permanent.”
He nodded, then gestured to his—her—body. “If it is, what do we do?”
She paused, then added, “There is always a way.”
Conan looked at her, really looked, and saw not just the borrowed features but the person inside them. “You sound like me and I don’t know if I like that…”
Ai rolled her eyes. “Tsk, a narcissist indeed.” The moment hung between them, stretched taut by everything they could never say. “We’ll need to tell Agasa.” Hiabara deflected.
Conan shuddered at the thought. “He’s going to have a stroke.”
“He’ll be fine,” she said, and for the first time, her voice sounded almost like laughter. “He likes a good mystery.”
They grinned at each other, the gesture awkward and new, but true.
As the morning sunlight enveloped the house, and the world, having flipped inside out, finally seemed to come to a standstill. Together, they sat in silence, two individuals seeking refuge from themselves, anticipating what the next day might hold.
As the hours slipped by, Conan found himself glancing at Haibara more frequently. There was something about her gaze—at him, at herself—that felt... different. Almost gentle, in a way he couldn't fully grasp. Yet every time he tried to concentrate on it, a wave of emotions overwhelmed him, leaving him unable to draw any conclusions. Because somewhere, out in the depth of their hearts, the future was already rewriting itself.