Yes, I love soulmate AU's. I literally have about ten prompts written down. This one isn't angsty (yes!) but...the beginning's ok but it goes down in quality as you reach the end...better than nothing, right? 

You age until your 18 and then stop until you meet your soulmate.

He still remembered the first time he heard about soulmates.

He didn't know exactly why he realised. He just looked at his mum, looked at his dad, and had a eureka moment.

At night, when his mum tucked him into bed, he voiced the question that had been waiting to come out the whole day.

"Mummy...why does Daddy look older than you?"

He remembered that her eyes turned sad, but her smile was still in place. She leaned in, right next to his ear, like she was about to tell him a big secret.

"I'll tell you when you're older, ok?" she whispered, leaning back.

He was not happy.

So the next day, he went up to his father. It would have been better if he just listened to his mum. Adrien didn't know then, but his father wasn't the best at...being a father.

Gabriel had told Adrien things that a five-year-old really shouldn't know.

And now, 115 years later, he remembers everything.

She still remembered the first time she heard about soulmates.

A kid at the playground had gone around, asking every girl in their class, 'Are you my soulmate?'

Marinette asked her mum as they walked home from school.

"Mummy, what's a soulmate?"

Her mother had smiled at her, and said,

"A soulmate is someone who understands you. They'll know you more than anyone else in the whole world."

Marinette wide eyed, has asked,

"Even you and Papa?"

Her mother chuckled.

"Even Papa and me."

Of course, over the years, she realised what it really meant, and how it affected her.

In her world, you age until you're 25. Then you just stop. No one knows how it's possible. Everyone knows why, though. Once you meet your soulmate, you start aging again. No one Marinette has talked to can explain how they know who their soulmate is. Alya, her best friend, who met her soulmate a week ago, tried to explain. She didn't do very well.

"It's just...a tingly feeling. Like you haven't been breathing, but you don't realise, and once you meet them...you feel how it's like to breathe again."

Great description, Alya. Thank you. That wasn't helping Marinette at all.

Considering the fact that she was 54 (though technically she was still 25), she was pretty sure that whoever her soulmate was, she wasn't meeting him any time soon.

"C'mon, dude! For me? Please?" Nino begged.

Adrien wasn't having it.

"Nope. You are not going to drag me along as your wingman. She's your soulmate. Not mine." He ignored the pang the word soulmate caused, instead choosing to glare at Nino.

"Please?"

"Nope."

"Please?"

"No."

"Please?"

"No."

"I'll buy you croissants?"

"...fine."

"Yes!"

"Alya, I don't wanna..." Marinette groaned.

"C'mon Marinette! Think of the many favours I've done you over the years! Now it's time for you to be my faithful wing-woman! Please, Mari?"

"Sorry, no can do. He's your soulmate, Alya. If you need me, I'll be in bed. Sleeping. Like every other sane person."

"Please?"

"No."

"Please?"

"No."

"Please?"

"No."

"I'll buy you fabrics?"

"...fine."

"Yes!"

Adrien slouches in the seat, already bored. Nino and the girl next to him (Alya, he's pretty sure) are in an animated discussion about the media and its pros and cons. He couldn't care less. He gave a long, over-exaggerated sigh.

The two soulmates looked at him, both with apologetic expressions.

"So, Adrien, right?" Alya asks. He nods.

"Yeah, that's me."

"So, you met your soulmate?"

She notices the flinch when she mentions soulmates, and she immediately looks at him in understanding.

"If you don't mind me asking...how old are you?"

"Uh...I'm turning 120 this year."

Alya spits out the croissant she was eating. Adrien looks at it with a sigh. A perfectly good croissant, wasted.

"120!?" she whisper-yells.

"Erm...yeah." He shoots Nino an uncomfortable expression. Taking the hint, he immediately tries to change the subject.

"I thought you were bringing your friend with you?"

Not the smoothest, but it does the trick. Alya takes the bait, but not before shooting Adrien a worried look.

"Yeah, but she's always late. That's Marinette for you!"

"Wait, is that her?" Nino points off to the side, where a bluenette was approaching while haphazardly dodging tables and chairs.

"Yeah! Marinette! Hey!" Alya waves her hands around, ignoring the onlookers.

The girl looks around, spots Alya, and began making her way towards them.

She was pretty, with dark blue hair, almost black, and bright blue eyes. Adrien would've continued his evaluation, but was interrupted by the girl in question.

"Hey Alya! And...Nino?"

Nino nods. She then turns her attention to the boy sitting beside him.

"And you must be..."

He smiles at her, and holds out his hand.

"Adrien Agreste. Pleasure to meet you...Marinette, is it?"

She nods, and shakes his hand.

His eyes widen, and she gasps.

He feels a tingling in his chest. And suddenly...he feels like, for the first time since he turned 25, he was breathing again. Like he hadn't been breathing until now.

There really were no other words to describe it.

Her hand drops from his like a stone, and they both openly gape at each other.

"Uh...guys?" Alya waves her hand in the middle of their staring contest, trying to snap them out of it. No such luck. Nino looks at him, confused.

"Dude, I know she's pretty and all, but there's no need..." He trails off.

He then whips his head around to face Alya.

"Has she found her soulmate yet?"

Understanding dawns, and Alya slowly shakes her head.

The soulmates turn to look at their friends, who are obviously in shock.

"Right..." Nino turns to look at Alya, trying to send her telepathic messages. By some miracle, she understands.

"Uh, my mum called! I, uh, have to go! Nino, come with me! I'm sure my mum will be delighted to meet you!"

Nino nodded emphatically, glasses almost flying off the bridge of his nose.

"Yeah, so, uh, we'll be going now....seeyoulaterdudebye!"

And with that, the two left their best friends and soulmates alone, cackling all the while.

"So...you have nice eyes?"

She turns to look at him, sarcasm rolling off her in waves.

"Really? Really?"

He smiles sheepishly, eyes darting to look anywhere but her.

"It's my go-to when I get nervous. Besides, I wasn't joking. You really do have nice eyes."

The girl flushed a brilliant red, and damn if he wasn't going to try and get her turn that colour again.

"Pardon me for asking...but are you the son of Gabriel Agreste?"

Adrien winced, and that was the only answer she needed. Her arms gestured wildly, obviously embarrassed.

"I don't mean to be rude! It's just, Gabriel Agreste is my favourite designer, so I've looked at a lot of magazines, so that's why I thought you looked familiar, like, cute but hot, and oh god I said that out loud, killmenow."

He smiled wildly, stifling chuckles.

"Well, you seem to know a lot about me, but I don't know a lot about you."

Her blue eyes widened, clearly just registering the fact. Smiling, she told him,

"My name is Marinette Dupain-Cheng. My parents are-"

She was cut off by an extremely enthusiastic Adrien.

"Are your parents the owners of Boulangerie Patisserie?"

He took her blink as a yes.

"Does that mean I get free croissants?"

She burst into laughter, and it was the most beautiful sound he had ever heard. Maybe they still weren't used to this whole soulmate thing. But, so far, it seemed pretty...

Miraculous.

I am snorting at my own stupidity aka my pun. I am also groaning at the cheesiness of the last bit. But meh.

NOW LOOK AT HEARTBREAKING FACE OF SMOL CAT SON AND CRY WITH ME...

THERE ARE LITERAL TEARS IN MY EYES MY HEART IS BREAKING RIGHT NOW WHAT DID CINNAMON ROLL DO TO DESERVE THIS...

Just. Look at the face. The sadness in his eyes. How Chat is literally breaking down. I'M CRYING HERE....

*sniff*

I'll just be...over there...sobbing...tell me when he's happy again...