This is a collab project between myself and Sleeping Moon, who actually proposed this fantastic idea but gave me the honors of publishing the work. There will be more chapters and I hope everyone enjoys!

Disclaimer: We do not own either Detective Conan/Case Closed or Miraculous Ladybug and Chat Noir.

Chapter One:

Within spending less than two weeks in Paris as its new resident, Kudo Shinichi had made two peculiar observations: the first one is that the city streets were a much different affair than those from the busy, native metropolitan of Japan. Furthermore, despite the ridiculous rumor that a pair of 'superheroes' protected the citizens from 'terrorist' attacks, no one had died under her supervision. Not since she had traveled to this continent via an airplane (and in her defense, the cadaver she found in the bathroom stall did not count), and was wholeheartedly welcomed to stay under the roof of Sabine Cheng and her family.

Having worked closely in the Land of the Rising Sun with the then-rising actress Fujimine Yukiko as a costume designer, the two women remained in contact after the latter's inevitable retirement and marriage to Kudo Yusaku. Although both worried and curious as to why the daughter of her old friend wanted to leave Japan and come to Paris at such a young age, Sabine was also happy that there was someone else whom her own child, Marinette, could talk to other than the Ladybug blogger Alya Cesaire.

However, Shinichi remained as vigilant and paranoid as ever despite this well-placed stroke of luck. When she could not find any peace at night after a long day, the former detective would wander the Parisian streets alone with azure orbs narrowed in caution. Occasionally, both her ears and eyes would catch a lean figure dressed in black dancing across the rooftops as the City of Love slept soundly. Sometimes, Shinichi would brush it off and continue her walk; but on other nights, such as this one, the dark-haired sleuth felt her heart thrum in unadulterated fear.

Oh, how she wished this so-called superhero would desist these nightly patrols. Seeing people dressed in black only created more stress than necessary.

It reminded her too much of them.

She came here to get away from that. All the lies, the stress, the death. Chat Noir, or whoever was this nocturnal fool who continued to survey the city at dusk, sent a prickle of annoyance up her spine.

Just as her mind drifted further on the thought of Paris' vigilante, a large piece of rubble flew past her head and that was quickly followed by a piercing, agonized scream. When Shinichi whipped her head to the source of the noise, she felt what little color remain on her face drain as she stared at the horrifying scene with widened eyes. Standing on the Pont des Arts was a frizzy, ginger-haired woman and a small child, the latter being dangled by the ankle over the railing with a terrified expression while screams permeated through the air. Shinichi's mind whirled as she quickly translated what the assailant was saying to Japanese.

"I don't care if the lawyers claim that I'm not a suitable mother! I raised her, gave her the love and attention when you couldn't spare even an hour with her! She's mine! Mine, mine, mine, mine, MINE!"

Shinichi's calloused palms immediately went to the right side of her hip, but there was nothing to grip. The detective swore silently under her breath; after she had taken Haibara's antidote and shed the identity of Edogawa Agatha, her paranoia had reached to the point where she could not go anywhere without a gun. And Professor Agasa took it away from her because the laws of France did not allow anyone under the age of eighteen to possess a firearm.

But that did not mean Shinichi was completely defenseless.

Judging from the woman's outraged shrieking, Shinichi quickly concluded that she had been been married, recently divorced and lost custody of her child that was roughly the same age as her victim. Henceforth, the unnatural strength to hold a hostage who weighed roughly 57 pounds with a single arm would eventually fade, and she would have no choice but to drop the girl.

That's when I'll take her out. Shinichi thought, discreetly flipping the top of her wristwatch up. One dart should be able to leave immobile until I can contact the police. Professor Agasa might not have let me keep a gun, but he did increase the amount of tranquilizer. Especially for people who could be immune to a smaller dosage.

Inhaling a deep breath, the coffee-haired teenager slowly walked towards the bridge and gently addressed the Parisian woman in the proper language. "Ma'am, please put the child down." Crazed baby-blue orbs immediately met calm azure ones, but the grip on her hostage remained firm.

Wait for Ladybug and Chat Noir! A little voice in the back of Shinichi's voice said, one that the detective promptly ignored. Why should she wait for a false hero? These people astounded her with their firm belief in lies fed to them by social media.

Moments passed, and there was still no opening for Shinichi to use the tranquilizer watch. The hysterical target was still focused solely on her movements while the child became silent, her auburn-colored eyebrows scrunched up in pain and chubby face turning a bright shade of red.

It wasn't normal. This...was not normal.

The woman should have started to lose her grip by now, or at the very least start shaking from the physical strain. What is... going on here?

Not wanting to take a chance and accidentally harming the hostage, Shinichi quietly closed the device's lid before she took a few steps closer to the wild-eyed female, her hands raised in a placating manner. She could hear sharp intake of angered breathing, almost to the point of hyperventilation.

Calming her frazzled mind again, Shinichi addressed the woman again in French. "Ma'am? Could you kindly put the child do-"

What happened next, not even her keen eyes could fully catch nor comprehend. A blurred blob of black was past Shinichi, then a baton (which certainly seemed to not be one that was of a legal size to carry in France) extended to the clouds before the child was plucked out of the assailant's arms and gently placed next to the startled detective. Shinichi felt a low growl emit in the back of her throat as dark blue orbs landed on blonde tresses adorned with feline-shaped ears.

Chat Noir. Paris' pseudo cat-themed hero in leather. Fantastic.

Contrary to Shinichi's train of thought, the child looked at Chat Noir with obvious admiration brightening her doe-like eyes as he returned it with a small smirk on his face. "Where's Ladybug?" The little girl asked, starting to look around the vicinity for a young woman dressed in a polka-dotted spandex suit.

Chat Noir shook his head with a heavy sigh. "I'm afraid My Lady is a very busy person, little princess, but she will come soon. In about ten minutes or less." His emerald orbs glanced back at the deranged woman, then back at the foreign-looking stranger before narrowing in suspicion. "Until we've dealt with the akuma, why don't you go with this nice lady to a safe place? I might even convince Ladybug to give you an autograph!"

Although he was talking to the starry-eyed girl, Shinichi could read between the lines of Chat Noir's subtle order: Don't get in our way. Irritation began to boil in her veins. What right did he have to say those things? He even have the audacity to drag a child into this!

Inhaling a deep breath to calm herself, the sleuth looked down at the child and smiled. "Little one...what's your name?"

"Aceline." The immediate response reminded Shinichi just how trusting children were as she reflected that even at that age, the first time, she had been way too mature. Shinichi kneeled down to Aceline's height, her smile growing ever so slightly. "That's a very beautiful name, Aceline. Do you think you can run over to those people at that sweet shop nearby?" By now, Chat Noir knew that she was not a native Parisian with the Japanese accent she still carried.

"I need to talk to this guy really quickly, but I'm sure nothing will happen. I'll even keep my eyes on you the entire time. Maybe we can get an ice cream sundae later?" Be gentle and sweet with kids. That was a primary mantra she had practiced when working with children on a multitude of cases. They are innocent. They are pure.

And they should never be involved with a situation like this.

"Really? We can have ice cream together?!"

Shinichi nodded. "Mm-hm. Go ahead and go over to the shop. I will be there shortly. I promise." Aceline beamed and obeyed the detective, dashing into a nearby shop an elderly couple were peering out of. Ignoring a disapproving stare from them, she let out a small sigh of relief when one of them grabbed the girl and ushered her inside.

"What kind of game are you playing at?"

Shinichi ignored the angry gaze of amber eyes and quickly checked on the supposed terrorist, whom the supposed hero quietly knocked out with his weapon. Unconscious, pulse steady, and small bit of blood dripping down the back of her head from what could be a possible concussion.

At this point Shinichi wished she had smelling salts with her. Nonetheless, swift hands worked to bandage any injuries as she thought of how rough this idiotic act was. Well, she had seen plenty of stupid things in her short years being alive.

"I said," his tone was incredulous by now and the detective tried to stay focused on the task at hand. "What are you doing?" You know, she really wanted to ask about that baton sometime. It reminded her of her own gadgets in a sense.

"Hello? Earth to suicidal maniac." An azure eye twitched. "Speaking of suicidal, why the hell did you think you could go up against an akuma." Now she just felt offended. Shinichi turned her head to look at Chat and narrowed her gaze at him.

"And what gives Paris the right to call a false terrorist an akuma? I can assure that back in my country, citizens do not enjoy random people being called devils in their native language. It is an insult that implies negativity."

Chat blinked. "... False terrorists? I assure you ma'am, akuma possession are not a false thing." Oh great, now he was looking at her like she was crazy. Paris was supposed to be a break, not more madness. "I can also tell you that you have absolutely no place in going up against one. Keep your nose out of our fights. We haven't had any casualties yet, and you're not about to become one of them." His stern scold elicited a scoff from the detective's mouth.

"Trust me when I say I can take care of myself."

He looked ready to argue until a yo-yo flew past his face to a nearby street light. "Sorry I'm late!" The sound of her voice sounded familiar to the raven head but when she tried to place it, it was like something was preventing it. "Where's the akuma being kept this time, Kitty Cat?" Ladybug seemed to ignore the detective as she focused on her partner.

"Meow is sure it's the photograph in her hands. In fact," he purred. "I'm pawsitive." Both of the girls expressed their reaction to his joke with deadpanned faces; he chuckled nervously and scratched the back of his head.

What happened next wasn't physically possible even with special effects, her mind concluded. It would probably be a lot harder to wrap her head around what happened if she wasn't stuck in a younger version of herself for the longest of times. "What the hell is that?!" She chose to ignore the amused smirk on Chat Noir's face in favor for scrutinizing all the damage, or what should have been damage. Everything was repaired!

Shinichi turned her gaze back onto the spandex-suited pair, gaze becoming cold as ice. "I don't know what exactly is going on here, or if another 'akuma possession' happens in the area again, don't waste time worrying about me. I've dealt with more, realistic monsters than the one you took down tonight. Monsters...who would not hesitate to kill everyone you knew without a second thought."

Emerald orbs widened slightly before Chat Noir sauntered towards the civilian, though stopped far enough to use his weapon if he had to. "There might've not been any casualties tonight, yet I can't be pawsitive that you know the 'real' dangers of being around an akuma just as I know very little about your definition of 'real danger'."

Shinichi snorted. "I'm afraid I can't satisfy your curiosity this evening, chaton. Pandora's Box isn't ready to opened to the world just yet." With that being said, she turned away and vanished into the night.

That was the first time that Chat Noir saw this peculiar civilian. Nearly a week later, Adrien Agreste was introduced to her by his shy classmate Marinette before their first period began. Azure orbs started at emerald ones for a brief moment until the foreigner politely inclined her head.

"Good morning. My name is Kudo Shinichi, though I suppose in this country, it would be Shinichi Kudo correct?" She asked in nearly perfected French. "I'm a detective from Japan...well, I used to be." Adrien watched curiously as she winced slightly, as if struck by an invisible hand. "L-Let's get along."

After school and two photoshoots, Adrien hopped on his computer and looked up any information related to his new classmate. Dozens of detailed articles appeared on all four screens, most written in Japanese and based on unusual, gruesome investigations that happened. Furthermore, she just disappeared without as much as a trace for almost a year.

This person...was she an enemy….or a possibly alley to Ladybug and Chat Noir?

Any thoughts on this strange crossover? We would love to hear your opinions!