- x - x - x -

Part One: Strange

- x - x - x -

The fluorescent lights were too bright. Squinting didn't help much, but Marinette did it anyways. Half-blind, she walked into the classroom.

The classroom was much too loud. Pencils and paper were shuffling, shoes scuffling, and her friends were calling to her, greeting her with excitement. "Hey Marinette," they said, "welcome back." They bombarded her with questions as she climbed up the stairs to her desk. Asking about her health, her week off, her head. She smiled weakly, gave noncommittal answers (I'm okay, it was fine, it's okay), and concentrated on getting to her seat.

Alya's voice joined the chatter as soon as Marinette sat down. "How's your head?" Her best friend asked.

"It's alright," Marinette lied.

"Good, I'm glad," said Alya, "I've missed you, girlie."

"Me too," said Marinette. That wasn't a lie. The week that she'd been stuck at home had been painfully boring. Her parents had taken her computer and her phone and had limited Alya to a short visit each afternoon.

Although, even if her parents hadn't taken her electronics, Marinette doubted she would have used them. She finally had her phone back, tucked reassuringly into her jacket's pocket, but she could barely stand to look at it. The bright light from the screen was worse than the classroom's bright lights. Thankfully, both the Mr. Fu and the civilian doctor her parents had taken to her had assured her that her light sensitivity would go away before too long.

Marinette wasn't sure how long too long was, though. It already felt like too long, what with nearly a week having passed. Marinette was a 21st century teenager. She wasn't used to being so completely removed from her technology.

Something soft poked into her shoulder. Turning around, Marinette found two boys smiling at her. "Hey, welcome back, Marinette," said Nino, waving his pencil at her.

"Yea, welcome back," repeated Adrien. He was smiling at her, his green eyes locked with hers. Marinette almost forgot how to breath.

Cheeks coloring, she politely replied, "Oh, thanks guys. It's good to be back." Adrien's smile grew stronger and Marinette's heart fluttered.

Four, long years. Somehow, despite four, long years, Marinette hadn't managed to get used to Adrien's attention. She still blushed like a little girl. It was, honestly, silly. The four of them - Marinette, Adrien, Nino, and Alya - had become a close knit circle of friends. Why, on the first day of senior year, Marinette and Alya had nearly gotten into a catfight with Chloé and her hench-friends over the seats in front of Adrien and Nino.

They were like the three musketeers. Only, there were four of them. Also, two of them were dating. Some time in junior year, Alya and Nino realized they were two halves of a magnet and came clashing together.

"Did Alya tell you what happened on Wednesday?" Nino asked, grinning. His voice was a bit too loud, echoing sharply in Marinette's ears, but she smiled regardless.

"No, what happened?"

"Oh ho ho, let me tell this story!" Alya scoffed excitedly, crossing her arms and leaning back in her chair. "So, on Wednesday, the devil - oh, I mean, Chloé, whoops - thought that she could sit in your chair."

Marinette listened, giggling as Alya launched into her semi-dramatic story. I've missed being here, she thought. Sure, the classroom was too noisy and too bright for her poor brain, but her friends were here. And, after a week at home, Marinette felt socially starved.

Finally, Marinette was back, exactly where she wanted to be: surrounded by her friends.

It was there, surrounded by her friends, listening to Alya tell a story with a voice that was a wee bit too loud, that Marinette experienced a strange thing.

Alya was smack dab in the middle of her story when she suddenly stopped. Mid-sentence, Alya clamped her mouth shut and her head tilted a few degrees to the side. Then, her eyes seemed to zero in on the classroom door. It was like a predator focusing in on prey.

For some reason, this movement seemed oddly familiar to Marinette. Although, she couldn't quite place why. She couldn't recall ever seeing Alya do such a thing before.

Marinette's head began to ache.

"Hm, I'll tell you more after math class, okay?" said Alya suddenly.

Before Marinette could ask, why the wait, the classroom's door opened and their teacher walked in. Papers and pencils shuffled as students got themselves ready to learn. Marinette, on the other hand, was looking between Alya and the teacher. She had a feeling, a feeling like she was missing something, something big. However, as that feeling grew, so did her headache.

But then class started, and the teacher's loud voice interrupted Marinette's confusing thoughts. After giving her head a quick shake, Marinette focused on tolerating the cacophony around her.

- x -

Lunch was better. The world outside was cloudy and quiet. Marinette found herself with the other musketeers in the shade of their favorite tree, food spread in front of them.

"Seriously?" Alya said, incredulously, "Your father hasn't taken a vacation in eight years?"

"Yea, or maybe even longer," Adrien replied, his fingers playing with tab of his soda thoughtfully, "that's why it was so surprising. He's…" Rubbing the back of his head, Adrien sighed. It was as if he was struggling to find the right words, "... getting better."

"Better," Nino echoed, a small, empathetic smile pulling up at his lips.

"Yea, better," agreed Adrien, his eyes glazed a bit, "he's been… asking about my day recently. And I think it's honest. Like, he's trying to be a good father."

"That's wonderful," Marinette couldn't help but gasp. She, like Nino and Alya, were more than aware of Adrien's struggles with his father. For most of his son's teenage years, Gabriel Agreste had been cold and distant.

"Yeah dude, that's awesome," Nino said.

"Yeah," muttered Adrien, smiling. Marinette felt like she could melt in the glory of Adrien's smile. It was an honest smile, one that reached his eyes. Once upon a time, he rarely smiled like that. Now, it was becoming more and more common.

"Do you think he'll be okay with you going camping with us?" asked Alya excitedly.

Camping. That was another something new. Marinette used to avoid commitments like that, ones that would draw her away from the heart of Paris for too long. However, ever since Hawkmoth willingly surrendered his miraculous back to the Guardian, Marinette hadn't needed to be as alert. Besides that, there were three other superheroes that could guard Paris - Rena Rogue, Carapace, and Chat Noir. Marinette's superhero partners all regularly patrolled Paris, albeit on separate schedules now-a-days (due to being too busy for patrol coordination).

Paris could go a few days without Ladybug.

"I, well, I think so," Adrien replied nervously. The tab snapped off his soda, broken by his fingers increasing zeal. His whole face was a mixture of giddiness and worry.

The strange feeling came back to Marinette. There was something there, something to notice. Her eyes drank in features she was already well acquainted with: blonde hair, green eyes, and restless fingers that were now toying with the severed soda tab.

Today, Adrien was wearing a black hoodie. There was something about that too, something off. Marinette stared at it, frowning as her head began to throb again.

"Hey, uh, Marinette, are you okay?" Alya's question snapped Marinette out of her strange reverie. Blinking in confusion, Marinette noticed that Adrien was watching her curiously. Heat rushed to her cheeks and Marinette swiveled her attention down to her half-eaten sandwich.

"Oh, um, yea, I'm-I'm-I'm good." Oh lord, she was stuttering again. Marinette mentally smacked herself. A concussion was no reason for her to revert back to being borderline non-functional around Adrien.

Boom!

A loud crashing noise shattered the peace of the afternoon. Marinette lurched to her feet, her damaged brain kicking into autodrive. Akuma, was the first thought through her mind, even though was impossible. Still, the muscles in her body tensed and she glanced around frantically, trying to locate the problem. Concussion or not, Ladybug was always ready to save the day.

"You dick!" screeched a certain pompous blonde, "You dented my baby!"

About twenty meters away, at the edge of the parking lot, Kim was sheepishly scratching his cheek, "Oh, whoops, my bad." Chloé kept screeching, her finger rotating between jabbing towards the dent in her Mercedes to the offending soccer ball, a few meters away.

Marinette sighed in relief. Silly, she told herself, you're getting worked up over nothing.

Similar sighs echoed hers. Marinette's attention snapped away from Kim's misfortune and over to her friends. All three of them were standing too, looking as tense as she felt.

Strange.

Strange strange strange strange strange strange strange.

Her brain was misfiring, that word repeating in her thoughts so many times that it lost its meaning. She couldn't help but stare at each of her friends in turn. Adrien. Nino. Alya. She watched as their faces relaxed and then became apprehensive, like a kid who'd been caught with their hand in the cookie jar. Alya smiled guiltily and Nino laughed nervously. Adrien avoided eye contact, his eyes dropping down to the ground.

Strange. Why?

The sun peaked out from behind a cloud and stabbed at Marinette's poor retinas. Meanwhile, Chloé's screeching continued to increase in pitch, attacking Marinette's eardrums.

The pain in her battered brain skyrocketed, threatening to throw her off balance. Grunting, Marinette slid back to the ground and grabbed her head. Her broken, crazy head.

"Marinette!" The others gasped, and hands gently grabbed her shoulders.

"I'm fine, I'm fine," she whispered. The hands on her shoulders squeezed softly, and Marinette peaked her eyes open a bit. Two green eyes, embedded in a beautiful face, was hovering not too far from her own. Adrien. Adrien was crouched down in front of her, holding her steady. Selfishly, Marinette allowed herself to drink it in, to enjoy this momentary closeness.

"Are you sure?" he whispered, frowning with concern.

"Yes," she couldn't help but smile at his concern. He was so sweet, and always so prepared to protect her. That was why she, despite four years of being strictly platonic friends, still rocked a rather massive crush on him.

His right hand moved, shifting from her shoulder to gently cup her cheek. "Maybe you should go home and rest," he told her, his thumb rubbing along her cheek. A sound that wasn't entirely human gurgled out of Marinette's throat.

Maybe my concussion has some benefits, thought Marinette as smiled dopily. The concussion surely had a lot of negatives, such as the pain and the unpleasant medicines (both from French doctors and from Master Fu). However, having Adrien Agreste touching her face so very sweetly like this… yes, Marinette would happily count this as a plus.

Somewhere behind Adrien, someone started to giggle. But Marinette was much too distracted to care.

She reached up and placed her own left hand tentatively over his right. "You worry too much about me," she told him lightly, her tone playful. She was too dizzy to think logically about how embarrassing she was being.

"I always will, princess," Adrien promised with a lopsided smile.

Princess. Her brain glitched some more. Strange. That word was back in her brain. But, why was it there? Strange. Why was it strange? Marinette tried to ignore her addled brain and smiled back at her crush. It's not strange, she told herself. "It's okay, kitty," she told him.

Kitty? Why did she say that? Marinette blinked, embarrassed and confused. That's what she called Chat Noir. She'd never before slipped up and called Adrien that. Ever.

Adrien's face suddenly screwed up, shock coloring his expression. "Kitty…" he echoed, blinking several times. His hand reached up and touched at the base of his neck, as if reaching for something that was usually there. It was a movement that was familiar, in the same way that Alya's movements earlier had been familiar. Black, gold, Marinette's brain told her, familiar. Once again, her gaze fell down to Adrien's hoodie, drinking in the color. Black, black, black. What was she not realizing? Her headache was throbbing but she tried to ignore it.

"Hey!" A yelp from Kim interrupted Marinette's puzzling, painful thoughts.

"Marinette!" Alya yelled at the same time that Nino yelled,

"Watch out!"

It happened quickly. Adrien glanced sideways. Then, cursing under his breath, he shoved himself forward, pushing Marinette backwards. His hands wrapped around her head, cushioning it as he pushed her down against the ground. Not half a second later, the soccer ball whizzed over their heads.

"Damn it, Chloé, what the hell is wrong with you!?" Alya screamed, "You almost hit Marinette!"

"Cry me a river, Césaire," Chloé screamed back.

Meanwhile, Marinette bit back tears. Adrien had really tried to be gentle with her, his fingers carefully spreading out against the back of her skull. Unfortunately, even the slightest pressure was too much. After all, the knot in the back of her head was caused by no normal bang; she'd got it after slipping and tumbling down the Eiffel tower, like a total klutz. The only reason the impact hadn't killed her was because her body was supercharged with her borrowed share of Tikki's kwami powers.

"Shit, you okay?" Adrien hissed with worry. He stayed frozen in place, as if he was afraid that moving might hurt her. Honestly, it might have. Marinette felt like a twig about to snag. She tried to turn her focus on how Adrien's body was pressed to hers, rather than how badly her head hurt.

"Well, I'm far from purr-fect." Seriously, what was wrong with her? Why did she kept talking like she was talking to Chat Noir? It was as if some ridiculous part of her broken mind was now obsessed with her black leather partner.

"Uhh." Adrien swallowed hard, his face paling. Marinette closed her eyes, to embarrassed to hold eye contact any more.

The bell rang.

"Lunch is over," Nino's voice seemed to come from forever away.

"Right," Adrien coughed nervously and then helped Marinette stand up. She was a bit awkward on her feet, but Adrien was graciously willing to let her lean on his shoulder.

"Thanks," she told him as she rubbed at her temple. She looked everywhere but at him.

"Yeah, sure, any time," he replied absently. Off they went, back towards the school.

That was a cat-tastrophe, thought Marinette miserably.

- x -

Marinette was laying awake on her bed. The sun had set, finally bathing the world in soothing darkness. Marinette was toying with a small, black cat doll, something that Adrien had given her in her junior year. He'd won it at a carnival and had somewhat awkwardly gifted it to her. You're kind of my best friend, he'd told her, so here.

It was one of her favorite memories.

"Marinette, shouldn't you try to sleep?" Tikki asked as she floated over to the bed, "You need a lot of sleep to recover well!"

"Sure, sure… I was just... thinking…" It was hard to verbalize how she was feeling. All day at school, Marinette had been wrestling with that strange feeling. Over and over, she kept experiencing it. When Nino adjusted his glasses with two hands, when Alya bit on the eraser of her pencil, when Adrien stretched languidly in the middle of a history lesson. There was something bugging her about these mundane movements.

"Um, about that," Tikki chuckled apprehensively, wringing her tiny hands together, "maybe you should, well, think less? Your mind is pretty fragile right now."

Feeling a bit suspicious, Marinette sat up and narrowed her eyes at her kwami. "Fragile? Tikki, it's been a week since I hit my head. Why would thinking, out of all things, be bad?"

Tikki laughed a little, but the laugh was fake. "Oh, well, Marinette, it just… it's best for you to relax right now! That's, ah, that's all." But that wasn't all. Marinette was sure of it, watching how Tikki twitched her hands together. Tikki was, undeniably, a bad liar.

"Tikki," Marinette huffed, "I can read you like an open book. What's wrong?"

The kwami sighed. "Oh dear. I suppose you can." Tikki turned to look out the window and smiled thoughtfully. "Plagg has tried to teach me how to lie a few times over the centuries. It's never quite sunk in." Plagg was the name of Chat Noir's kwami. Marinette had learned that from some of Tikki's stories.

"Right," Marinette chuckled, "the only reason you haven't let slip the other miraculous holder's identities is because of the ancient magic." The ancient magic being the magic that kept kwamis from revealing their hosts as well as other kwami's hosts. It was the reason why Nooroo, despite being back with the Guardian, could not tell them who was Hawkmoth. Or, well, who had been Hawkmoth.

"Yes, and you know that there is a reason behind this secrecy."

Marinette sighed deeply and then quoted Master Fu, "It is for the safety of both the miraculous holder themselves and their loved ones. Identities should be kept secret until the team is ready." Well, that wasn't exactly how Master Fu had said it. He'd talked about maturity levels and bonds within the team. Marinette could still remember how Chat Noir had grimaced and Rena Rogue had rolled her eyes.

Regardless, Master Fu was the still Guardian (for the time being). Yes, he'd passed his own miraculous to the new Carapace, but Carapace was but in training. Until Carapace was ready, Master Fu would be their Guardian and so his decisions, they respected.

That meant that Marinette had no clue who Master Fu had chosen for Rena Rogue, Carapace, and, for that matter, Chat Noir. Despite years of training and patrolling with them, she was no closer to figuring it out than the day she first met each of them. She hadn't even the fainest clue as to who each of them might be.

"Good, I'm glad you remember," Tikki chirped happily, before flying away from Marinette.

"Tikki," Marinette said, exasperated, as her kwami tore into a bag of cookies. "Why are you telling me not to think?" Did Tikki really thought Marinette would drop the subject that easily?

"Ohm, itsh cohm-phli-cay-ded." Tikki was almost impossible to understand, her mouth full of cookie. Marinette frowned and waited for Tikki to swallow. The kwami did so very slowly, her eyes watching Marinette, as if hoping that Marinette would change her mind about the question. Finally, Tikki gulped down the last bits of cookie and spoke again, "Marinette, I'm sorry, but I don't want to explain. I'm afraid if I explain, then you'll definitely notice everything more."

"Notice… wait, notice what?" Marinette asked frantically, clapping her hands to her cheeks, "Like, notice little things that are like oddly familiar, but like, they aren't?" Her mind immediately went back to all the things that had caught her attention that day at school.

"Oh. Oh, no, I shouldn't have said that," squeaked Tikki before shoving another cookie in her mouth.

"No, Tikki, tell me! It was driving me crazy at school. I kept seeing my friends do stuff, stuff that felt like… I don't know, like stuff I've seen before. But also like, not. Ahh…!" Oh lord, she was getting another splitting headache. Marinette flopped back down against the bed, rubbing her temples.

There was a silence. Tikki chewed her cookie and Marinette tried to stop the pounding in her head. Eventually, the kwami spoke again. "Look, Marinette... give it another week. Once you get better, you'll stop seeing it again." Again? What exactly did that mean?

Marinette stared at the ceiling, drowning under the weight of her own thoughts and her splitting headache.

She stayed like that for nearly half an hour, the minute hand on her wall clock sneaking downwards at a deceptively fast pace. Tikki gave her space, finishing off the rest of the cookies before taking a nap at the other side of the room.

Drowsiness was just starting to tease at the edges of her consciousness when there was suddenly a soft tapping.

Marinette sat up slowly and rubbed her eyes. Had she imagined that noise? Then, she heard it again, the sound of someone tapping on her window.

Chat Noir.

She could see the glimmer of his form, lit by the moonlight, outside the window. Smiling a little at this curious surprise, Marinette crawled out of bed and made her way to the window. She pushed it open and stepped back to let her favorite cat in. "I was starting to think you fur-got about me," she told him. Chat Noir smiled guilty.

"Please, I could never," he chuckled.

Neither could Marinette. Over the last two years, the two of them had developed a strong… something. Friendship, one could call it. Although, it was really something more than that. Back in Marinette's junior year, Chat Noir had visited her almost every other night. He'd been a bit of a mess during that time, seeking comfort and friendship. Marinette had never quite figured what had caused the sudden change in his behavior, but she knew it had to do with the explosion at the Agreste mansion. Regardless of the reason, Marinette had been happy to be his rock.

He was her teammate, after all. Well, he didn't know that, but she knew.

Chat Noir stepped close to her, invading her personal space. However, Marinette was more than used to this. His visits to her were mixed with a weird sort of intimacy. "How's your head?" he asked, his green eyes softening.

"You heard?" Marinette shrugged and smiled, not wanting to concern him too much, "I'm alright now. But a couple days ago, your ugly face would have hurt too much to look at it." Her words were playful, carrying no actual weight. She loved his face more than she should have.

Chat Noir rolled his eyes, then spoke earnestly. "I'm sorry I didn't visit. I thought, maybe, you'd need your sleep. I figured you wouldn't thank me if I woke you up in the middle of the night." She probably wouldn't have. Normally, Chat Noir's two and three AM visits were no big deal. But, so soon after her concussion… maybe not so much.

"Speaking of that," Marinette said thoughtfully, glancing at the clock, "you're here early." Eleven AM was several hours earlier than usual.

"I know, but I wanted to see you," he replied with a shrug.

Then, he took another step forward and, swift as could be, scooped her up into his arms. "Hey," she playfully whispered, whacking at his chest, "careful with me."

"As always, princess," he told her as he walked over to her bed. It should have been odd, this boy who wasn't her boyfriend, carrying her like this to her own bed. However, it was the opposite of that. It was downright normal. This was just a part of their weird intimacy, which had started over a year ago.

Chat Noir liked to cuddle. And, as it had turned out, so did Marinette.

Even though it should have been awkward, it never felt that way. It just felt… right.

That's how it felt now, as Chat Noir lowered her down onto the bed and then plopped down himself. He was already purring as he wrapped himself around her and buried his face into her hair. Her hair, which wasn't contained her typical, cute pigtails. That was how comfortable Marinette had become around Chat Noir - she was okay with him seeing her, hair down and in pajamas

"These are cute," he murmured into her ear, his claws poking at the design on her pajama's tank top. Cartoon cats were printed on it, each frozen in different, silly poses.

Coloring a little, Marinette admitted, "It reminded me of you."

Her teammate's grin was almost blinding. She loved seeing him smile. Especially when it was a true smile, one that reached his eyes and lit up his whole face.

"You're cute," he whispered, his voice becoming a bit husky. Shivers ran down Marinette's spine. Not bad shivers, necessarily, but unexpected ones, nonetheless. She chuckled nervously. Don't, she chastised herself, that's not the nature of your relationship. Her and Chat were purely platonic. It was best that way. She was in love with Adrien, and she couldn't lead Chat on like that.

That, of course, didn't stop her from closing her eyes and wrapping herself a bit closer to Chat Noir. After a week of bad headaches and doctor visits, she wanted to indulge in this pleasant moment.

He purred and his whole body shook gently. If Marinette could have purred, she probably would have. However, ladybugs don't purr.

One of his hands found her cheek and rested against it. Marinette sighed blissfully. There was something so very sweet in the way he touched her. Another wave of pleasant shivers ran down her spine. They only worsened when he then began to move his thumb, brushing back and forth against her cheek bone. She had to suck on her lower lip to keep herself from making any embarrassing sounds.

This is Chat Noir, she reminded herself, not Adrien. And yet, it was so familiar as to how Adrien had touched her earlier. She opened her eyes and found his face only a few centimeters away. His breath tickled her lips.

Green eyes, wrinkling at the edges as he smiled.

Familiar. Strange.

Her mind couldn't make up which it was. Both words knocked about within her brain, fighting some unseen and rather confusing battle. Her head started to hurt again and she squeezed her eyes shut.

"Marinette…" he spoke softly, kindly, "Are you okay?"

"Just purr-fect," she replied sarcastically, as she rubbed her head, "you know, other than the concussion." He didn't laugh at her pun. She peeled her eyes back open and found him watching her, an odd expression painted on his face. Concern? Surprise? Fear? She couldn't pin it down.

"Marinette." His tone was almost pleading, desperate. Marinette blinked, unsure what he wanted or why he seemed almost… scared. "Do you… did you… uh…"

His claws moved nervously, tracing invisible patterns on her skin. Heat began to build up within Marinette, as well as confusion.

"Do I, what?" She whispered back.

"Do you know?"

It was a simple statement, but it felt massively important. Marinette frowned, lost. What did he mean by that? Know… what? She tried to think about it, but it was like headbutting a mental wall. There was something stopping her, crushing down on her thoughts painfully. Don't think about it, it seemed to tell her.

Her silence must have made Chat Noir even more nervous. He squirmed, somehow managing to push himself closer to her. The heat from his body seeped into her. "'Cause, it's okay if you do," he whispered, almost conspiratorially, to her, "I know Plagg won't like it, but, Marinette, I feel something… I…" He was breathing hard, his words spilling out of his mouth. One of his hands found hers and his fingers intertwined with hers.

Her head hurt so much. She was trying to think about it, trying to figure out what he thought she knew. What wouldn't Plagg like? Hell, her head was about to explode.

She whimpered, and Chat grew still. "My head," she whispered to him, "it hurts. I… don't know what you're talking about. But I feel like I should."

His free hand rubbed gently at her forehead. Chat Noir sighed deeply, "You're warm. I shouldn't… stress you out like this. I'm sorry, I just thought that…" His voice died again. She whimpered and moved, pressing her head against his chest. She was keenly aware of his hand, squeezing hers. She was also keenly aware of how tired she was.

Marinette yawned and intertwined her legs with Chat's. "I'm sorry, Chat," she told him honestly, "I'm not good at thinking right now."

"That's okay," he told her, sighing, "sleep, princess."

Her eyes were heavy. So, she shut them and allowed herself to drift off. Thanks to her concussion, sometimes sleep came for her quickly. As she gave in to the call of her dreams, she whispered to him, "Good night, Adrien." She was asleep before she could realize she had used the wrong name.

- x - x - x -

A/N: Well hello there.

I hope you've enjoyed the first chapter of Diagnosis!

This story is, for me, both a fun exploration of how the secret identities work in the Miraculous fandom as well as a warm-up. It's been months since I've written anything and I feel quite rusty! After finishing this story, I plan on continuing Entropy, which is my thirteen-chapter Miraculous story. I apologize for the hiatus in writing - my desire to write comes and goes. :) I'm glad to be back to writing, though! Fluffy romance ain't gonna write itself, after all!