Study in Romance

Disclaimer: The works of Detective Conan and Magic Kaito belongs to Gosho Aoyama-sensei.

Warning: KaiShin relationship.

A/N: The original prompt was from Shana-Fujioka, I kind of want to establish the background first before jumping straight into the scene. It was supposed to be a one/two-shot but turned out to be a multi-chapter thing. Although I dislike having to work on two fics at the same time (messes up with the writing and all) but they are very different in nature. I'm hoping it sounds like a RomCom, though I'm bad at comedy/humour (or so I'm told). I'm not going to tell you the original prompt (go look for it if you're curious) as it'll reveal too much of the story.

Enjoy~

Ch01: How it all began

"Just a little bit more..."

Shinichi tries to keep still, to stop trying to run out of the bathroom screaming 'harassment' or 'molestation' as he felt the soft brush glide over his skin. He resisted the urge to lean away from the touch, not that there was anywhere else to lean away to seeing as he was practically boxed in the relatively cramped space of the bathroom.

'Why did I agree to this?' He moaned inside his head, 'I should have kept my mouth shut and my head down. But No, I had to open my mouth. And it just so happens 'kaa-san was within hearing range…' Shinichi's internal rant continued along similar veins, dissecting his every action from the very beginning. This was the only way to keep his mind sufficiently occupied and to stop himself from fidgeting.

Shinichi's mind wandered back to a month or-so ago, the day when Haibara called him up.

"Kudo-kun," she addressed through the phone, no longer afraid of being overheard now that The Organisation has been all but disbanded and only lesser members of the notorious criminal group remained on the streets, "would you mind coming over to the Professor's place today?"

"Something wrong?" Conan placed down the kiddy book he had been pretending to read, his focus now dialled into the young voice through the speakers.

"Nothing grievous I can assure you. Just wanted to test out a theory and I needed your presence." There was no sense of urgency in the voice, only mild seriousness and a hint of curiosity.

"I'll tell Ran I'll be staying the night at the Professor's then." He hopped down from his seat, stretching up his arms with the phone between his ear and shoulders. "Unless you need me for longer than a single night. Not that it matters much seeing as it's the holidays."

"It depends really…" Hearing the scientist trail off on her sentence made Conan slightly apprehensive in making the journey.

"Anything in particular I should know beforehand?" He had a suspicion on what the scientist wanted to test but he did not want to have his hopes raised.

"Nothing detrimental."

"Right..." Her reply added on evidence on what to expect. "I'll tell Ran now. See you in a bit."

The call terminated without any greeting, though neither end had expected one.

"Ran-neechan!" Conan called into the girl's room. She, and many others, were still kept in the dark about Conan's identity. Although The Organisation is no longer a threat, the discovery of a drug being able to turn a teenager to a child was too much a risk for anyone with an iota of greed. He did not tell Ran the truth even when he knew there was very little harm in her knowing. She was too honest, too forgiving, and too understanding. Shinichi did not doubt Ran would be quick to forgive for the lies he told, for the indiscretions he took against her, and for causing her all the tears. It was himself he could not forgive, which was why he chose never to inform her of his time as Conan, even if he returned to his original age. It was something like trying to punish himself for her sake.

"What is it Conan-kun?" Ran's head peeked out from the doorway, she was all dressed up to the nines and looks to be in the process of putting on makeup.

"Are you going out in the afternoon?" Conan decided to ask first before giving telling her of his intentions for the rest of the weekend.

"Yes, I'm meeting with Sonoko and Kyogoku-san. One of his friends is in town and we're going to show him around." She stepped out of her room to face Conan fully.

"Is he someone I know?" He had to ask. He had to know. But at the same time, he dreaded the answer. He could practically see the last link to his past, his history, cracking and disintegrating under all the lies.

"Not really. The first time I met him was from a tournament. I watched him compete..."

Conan sensed there was more but he did not feel he would be up hearing about it.

"Then you should go have fun." It was an implicit blessing he, as Shinichi, was giving to Ran. Telling her to pursuit her own happiness.

Ran gave him a strange look, as though she could not believe he had said that. Shinichi wondered that perhaps she knew who he was all along. That she only kept her silence because she trusted Shinichi enough to tell her when the time is right. But there will never be a right time. Not now, not in the uncertain future. Which was why Conan, and Shinichi, decided it would ad best to let her go.

"Are you sure?" She asked for confirmation, hands gripping onto his small shoulders. It once again reminded Shinichi of the changed circumstances.

"Of course I am!" He gave the best smile he could manage, all adorned with sugary happiness. "I was just about to tell you I would be going over to the Professor's and stay for several nights!"

The moment of silence intensified the tense atmosphere between the pair of mock siblings. Ran stared straight into his eyes, never weakening in its probe for falsities or pain. Conan saw how the edges of her mouth tensed just a fraction, felt the grip on his shoulders tighten. He was quite sure she was trying to urge him to take some form of action, to tell her the truth. But Conan just could not do as she hoped. Instead he let himself cocked his head in a somewhat innocent manner much like the boy his age would when faced with such a serious situation.

"Ran-neechan?"

"It's nothing Conan-kun. Go grab your overnight bag, we can walk part way together." Her smile was strained as she waved him away. Conan did not bother to linger around and dashed off into the shared room.

When he came out of the bedroom, Ran was already waiting patiently by the doorway with her purse set on top of the shoe cupboard. Her red lipstick coupled with the light brush-on made Ran unlike the childhood friend Shinichi was used to seeing. His Ran was more down-to-earth, quite the opposite of this sophisticated version. Though her beauty remained unchanged.

"Ran-neechan, you look...really pretty." Conan was sure his words were not enough to describe the beauty in front of him.

"Thank you." She leaned down and kiss his forehead. He was surprised her lipstick did not transfer onto his skin when he rubbed the area with the back of his hand.

Conan looked perplexed, as he was not sure whether Ran was thanking him for the compliment or for something else entirely.

'Though if she had always suspected my identity, she would probably be thanking me for my blessing…' And he was not sure how to feel about that. The only thing that he was certain was not feeling overly saddened by this prospect. Sure, there was a twang pulling at his heart at letting Ran go, but his logical mind had told him this was better than the not-seeing-each-other-but-still-attached phase they kept having.

"Now don't stay up the whole night." Ran reminded when they came to the intersection they needed to part at, where Ran would head towards the station and Conan towards the Professor's place.

"Of course!" He chirped, smiling at the brightness in her eyes.

"And remember to call if...if there's an emergency or something ok?"

It seems Ran also sensed something was different about his sudden sleep over.

"I will." He nodded with a certain degree of seriousness, "I promise to let you know."

She hugged him, tighter this time, not minding the creases that were forming in her dress.

When Conan arrived at the Professor's place, he was immediately towed to the basement lab by Haibara.

"I thought you said you're not rushing anything." Conan followed in rushed steps, careful not to trip over his own feet as they all but ran down the dim staircase.

"No, but I really do wanted to confirm something." She stayed cryptic in her words as she took out several syringe and a single vial of clear liquid. "Arm." She motioned for his cooperation, which he gave without complaint.

She took a syringe and extracted a decent amount of blood before injecting him with the clear liquid.

"What's this then?" He had to ask as he watched with grim fascination, the liquid was slowly injected into his bloodstream so he had the right to ask about its effect.

"Not sure, that is why I wanted to test it on you."

"Haibara! I know I said I'm willing to be a guinea pig but I don't mean it literally. I'm not a lab rat."

She chuckled at his flustering but kept a firm hold on his wrist as he tries to extricate his arm from the sadistic scientist.

"It won't hurt you or cause undue harm if that's what your concern. I needed to observe your reactions first."

"Does it include me trying to freak out at not knowing what this is?" He motioned towards the empty vial on the table.

"Don't worry." She pulled out the needle and applied pressure onto the small puncture wound.

For the rest of the night, he had been paranoid and on the edge. Each time Haibara glanced at his direction, he nearly jumped and immediately froze. The next afternoon, twenty-four hours after the injection, Haibara pulled him back into the lab and extracted another syringe full of blood.

"Are you sure you're not secretly a vampire?" He commented offhandedly, "I only just replenished my blood."

"You know, I might just hurt you." She diverted her attention from the syringe back to him, subtly saying she had a sharp object in her possession that was currently jabbed into his elbow.

"Never mind, pretend I said nothing."

Casually, he rubbed at the wound when the process was finished.

"So, what were you expecting?"

"Not what I've observed for the past twenty-four hours that's for certain." She fiddled around with several clear containers, emptying the blood into one and picking up the pipette to extract some and relocating it to a small glass plate.

"Now can you tell me what I've been injected with?"

"That," she motioned back at the vial that had been left unattended on the table since yesterday, "was the liquid version of the trial antidotes."

"What?! You just injected that directly into my bloodstream?"

"Yes, and there had been no changes from you. Much like what I've been suspecting. You've developed immunity toward that particular formula."

Shinichi's shoulders sagged. He was immune to the chemical compound, which means there was no hope left. Funny how he just gave up on Ran and found out it was really for the best.

"However," her voice startled Shinichi from his mild depression, "I have something else in the works, seeing as you did recover the original data, which I have been working on and finalising. The sole reason why I wanted you here this weekend."

"Then this means…?"

"Yes Kudo-kun, I do have an actual finished and perfected antidote. This test would only confirm for me the percentage of survival for you." She sighed, looking at the locked fridge to the side. He suspects that was where the antidote was stored. "However, I must say, it doesn't look too great."

"That's fine." He debated whether it really was worth going through the painful process of transformation now that Ran was pursuing her own happiness without him. However, it was still his life and he did not wish to go through the whole growing up process again. "Any confirmed time?"

"The sooner the better chances of your survival I'd say."

"I'll call 'kaa-san to let her know and we can collaborate the story. Conan will have to leave abruptly due to family emergencies. Thankfully 'kaa-san just came back because of that fit she had with 'tou-san flirting with a fan of his, so she should still be next door."

Arranging everything took less effort than they suspected. All it needed was for Edogawa Fumiyo to show up at the agency where Kogoro had been sitting and drinking beer, having her ask for Conan's whereabouts in person. That very same night, Haibara handed him the antidote, which was in the form of a liquid injection instead of a pill.

"A higher chance of you returning to your old self." She stated clinically. "I must warn you, the chance of success is still quite low, a meagre 48 percent."

"Any chance of fatality?" His morbid curiosity piqued.

"50 percent. The remaining 2 percent have you staying as Conan for the rest of your entirely too-short life."

"Meaning?"

"Your body would ultimately fail you when you reached your actual age."

His eye's widened at the declaration of possible death.

"And you? Would the same happen to you?"

"Thankfully no because I haven't been using as many of those temporary antidotes to cause enough of the detrimental effect. However, that's offsetted by the effect that I will grow slower than normal."

"So this so-called poison is more like…"

"A fountain of youth." She sighed, her strength suddenly leaving her with the breath as she slumped against the nearby stool. "We're being both God and the Devil here, going against the flow of time."

"Thank goodness that not many know about our stint then." He looked at the implement in his hands.

"You didn't tell FBI? Or anyone else?"

"Of course not!" He had been pressured into telling but careful wording had made the FBI back off his case. Though Akai Shuuichi probably knows something but no words were exchanged between the agent and himself regarding the issue, so he could assume that the agent was not too bothered by his predicament. Shinichi suspects it was the same with Bourbon. He hoped the two would not confront him any time soon. The only person he hinted towards was Takagi but that was to uphold his promise to the man. "The number of people in the actual know is still the same."

"Good, let's have it that way." She seemed relieved. "Though I'm surprised you didn't tell Mouri-chan."

"She's better off not knowing…" Turning the capped syringe in his hand, he carefully pocketed it back in his jacket. He would be taking it back in the safety of his own home.

"Then I don't need to tell you that you should pace Kudo Shinichi's return?" She was apparently suitably surprised by his statement but hid her reaction well. Shinichi did not blame her seeing as the whole world had thought Ran and himself would eventually end up together.

"Who do you take me for?"

"A lovestruck idiot that's what. Why the change of heart?" There was definitely more concern lacing her voice than curiosity.

"It's not fair on her, she waited for so long for Shinichi's return but the person coming back to her will be different from the person she remembered. Also..." He left out his own insecurities about not living up to the expectations and his self imposed punishment unsaid. "It's better this way. If your calculations are correct, I'm more likely to end up dead."

He left several written notes with Haibara to hand over to the Detective Boys, left a voice message on Ran's phone because she did not pick up during his call. When all his loose ends were tidied up, he went back to the Kudo Manor using the underground passage. His mother was just tidying his room when he entered.

"Shin-chan." She enveloped him in a tight hug. "Are you absolutely sure?"

"Either way, 'kaa-san, Edogawa Conan didn't have long to live. Why not let me have it my way." He returned the hug with the same amount of conviction as his mother, though his short arms barely managed to wrap around her neck.

"Your father said don't die." He wondered how that particular conversation went with his parents. His mother had been angry when she left for Japan. To suddenly call his father and inform him Shinichi was likely to die, it was a wonder his father did not immediately fly in.

"I'm in the mind to stay positive but..." he trailed off once more before gathering the resolve to ask. "Did Haibara tell you?"

She nodded, her arms tightening around him.

"Then..." Shinichi was not sure whether he should say goodbye at this instance or not. But one thing is for sure, he did not want his mother here inside the house during his transformation. "Maybe you should leave the place for an hour or so. You know, just that, it'll be quite disturbing..."

"But Shin-chan," she started her protest but the determined look from him must have meant something to her. "Alright, but only ONE hour." She huffed as she shuffled out of the room.

Shinichi kept his ears trained for the front door opening and before clicking close. He waited for a full ten minutes before actually settling on the bed and pulling out the syringe from his pocket. It felt ominous even for something of such a size. Not wanting to give himself any time to think, he quickly shed his clothing and took the needle to his elbow. He watched as he plunged the syringe, emptying the liquid in a quick motion. Not a second after he pulled the needle out, Shinichi felt heat. Followed immediately by stinging pain along his spine. His joints ached and his bones burned. He tries to muffle out his screams of pain with his pillow. The transformation was more intense than before. He could feel his muscles stretch to accommodate for the lengthening bone. Each of his nerve ending felt as though it was on fire. At one point, he felt his body arched as though to stretch out the skin.

Through the haze of pain, a stray thought drifted through his mind.

'I think I missed telling someone about this…' In the midst of the pain, his brain was still trying to work out who he forgot to inform. He messaged Hattori, left Ran a voice message, written notes for the children, that should have been all of Conan's friends. As another wave of pain hit, Shinichi accidentally hit the bedside lamp, which shattered on the floor with a resounding crash. His mind then drifted between bouts of heat and pain to the sensation of ice. His thoughts becoming incoherent as it tries to ground itself to something other than the pain. 'Wait, isn't it that thief's heist tonight? The one I had intended to go?' He let out another scream as the heat returned to burning his every fibre of being. 'Why is the transformation taking so long.' He tries to gulp in more air as he curled up on the bed, wondering if he was really going to die that moment.

The pain lasted for what seems like an eternity, to the point where Shinichi passed out.

Shinichi had to shudders at the memories of his final transformation. He still has phantom pains just thinking about it. It was that traumatic.

"Shin-chan, don't move." His mother warned as she applied lipstick on his lips.

'Why did I say I was bored? Being stuck inside the house is better than being in this predicament.' Shinichi realised how suspicious it would seem if Conan queenly disappear for Shinichi to immediately come back to Beika, hence the need for him to stay hidden for at least a few months, or until it felt natural for Shinichi to be appearing. They figured that since it was nearing the end of the holidays, they might wait until the start of the new school term for him to come back. Which means Shinichi was not allowed out of the house until at least the end of next week. He had been patient of course, but having read nearly the whole library and have finished all his missed school work, there was nothing else to occupy his time. His parents had stayed for the whole duration since he woke up, to keep him company, but even they were not able to alleviate his boredom. To which his mother suggested attending that dinner party she had been invited to.

"If you keep moving, I won't be able to draw the lip line." She tapped the lip pencil on the tip of his nose to remind him who was in control. "Thankfully, you've inherited my bone structure, edging on the delicate side, so you won't need a silicon mask or heavy reconstruction."

A few more strokes with the pencil, she finally pronounced his disguise complete and let him look into the mirror. He nearly could not recognise himself. Gone were the more angular cheeks and jaw, in its place were something softer but still quite defined. His eyes remained the same shade of clear blue, reminisce of the deep sea, but was bordered with dark eyeliner making his eyes larger than normal. The pale shade of silver and purple coloured his eyelids, complimenting his eye and bringing out the hidden sparkle.

"Here." His mother handed him the choker the Professor repurposed from its previous owner, namely one Okiya Subaru a.k.a. Akai Shuichi. "I made sure the dress would go with the accessory." She handed him a bunch of fabric, which he assumed to be a one piece dress. Though, by the amount of fabric now in his arms, Shinichi had a feeling it would be quite revealing.

"You do know I don't have the body type for something like this right?" He reminded his mother of his actual gender despite his makeup making him looking more feminine.

"Of course Shin-chan, which is why we also have these. I knew it would come in handy." She pulled out a box and pushed it into his arms. "Make sure you put on everything."

Once the bathroom door shut with a click, Shinichi opened the lid. He could not stop the blush from forming and growing to exponential proportions, surpassing the blush-on currently painted on his cheeks. He was speechless, mouth opening and closing like a fish gulping in water.

Lying innocently in the paper box were black lacey garments. Shinichi dangled the first piece between his forefinger and thumb, holding it away from him like it was contaminated. He could see additions were added to specific parts, extra padding to make the fabric stiffer and to give the wearer the required shape. The second piece was just as lacey, just as revealing, and not leaving much to the imagination. It looked uncomfortable enough and Shinichi had to once again question whether he wanted to go through with the whole ordeal just to alleviate his boredom.

"Shin-chan, you ok in there? Do you need help?"

"NO! No, definitely not." And there goes his choice of being able to bail out. Taking a deep breath, Shinichi bravely discarded the robe he had been wearing and proceeded to dress himself.

-TBC-