Demigods: In Paris (a Miraculous Ladybug and Percy Jackson crossover)

Alya has a scoop

Dedicated to @hoffera for all the votes and comments that filled up my notifications :)

Marinette collapsed into bed, too exhausted to think about the fight she just witnessed. Tikki bobbed over to the window, eyes wide. "So it's true," she whispered squeakily. "They really are still out there..."

Marinette fell asleep before she could even begin to wonder what her kwami meant.

In the morning, Marinette was too busy trying not to be late to school to worry about it. She only just remembered as she was skidding out of the door that she had to take down her posters of Adrien before her crush came to hers for the party that night and saw them. But before she and Tikki could finish that, Marinette noticed a homework lying under the stacks of design ideas that she hadn't done, so she had to complete that, and by the time she got to school, she had already missed most of the first lesson.

It was halfway through the second class of the day that Marinette remembered her encounter with Percy and Annabeth yesterday, and the ensuing fight, then what Tikki had said... Who were her new friends? Had it been a real monster they'd fought? Where had Percy's sword come from? How had they learned to fight like that? Who was Chat Noir, and how had they known who he was too?

It was all wayyyy too confusing.

"Hey girl, check this out," Alya whispered, leaning over to show her friend a video under the desk. "It's the fight from yesterday! And look- it seems like Ladybug and Chat Noir had help!"

"What?!" Marinette yelped quietly, focusing on the screen. It showed her alter-ego, Ladybug, swinging past the monster she'd fought yesterday. In the background, she could see Percy wielding his sword, but his face was blurred by the action. Above, Annabeth was wrestling with the Hydra's head, but her blonde curls obscured her face.

"It's so annoying," Alya continued. "No matter where I pause it, you can't see their faces clearly. I can't even really tell what colour their hair is in the lighting!"

Marinette kept watching, then frowned slightly as she started noticing details that she didn't remember from the fight. There, she called down her lucky charm. The snake head with sunglasses fell out of the sky, but instead of the conversation she'd held with Percy, Ladybug just looked around for a couple of seconds, then took off the glasses herself and held up the gross monster face. The hydra turned to stone, like she remembered, and Chat used his Cataclysm, but instead of just leaving rubble, an akuma flew out of the stone.

"What?" Marinette blurted, as Ladybug used her yo-yo to purify the akuma. She definitely didn't remember that.

"Shh," Alya hissed, hiding her screen as the teacher glared at them disapprovingly. When she finally continued the lesson, Alya said, "they carry on like that, the akumatised person walks off, Ladybug and Chat Noir swing away and the other two just walk off like completely normal people! I wonder who they are!"

Marinette just blinked. She was really, really confused.

"...and there was an akuma and person inside the stone monster!" Marinette finished explaining to Tikki, in the girls' bathroom. "That didn't happen... did it?"

"Ah, the joys of the Mist..." Tikki sighed nostalgically.

"The what?"

"Oh, just a form of magic that makes people see what they expect to see. It's similar to the magic in your suit that stops you being recognised."

"Wh- there's magic in my suit?"

"Of course! What, did you think that tiny mask could hide your identity? No! But the magic means that nobody can recognise you as Marinette whilst you're Ladybug!"

"So... you're saying Percy and Annabeth can use the magic that's in my suit?"

"Something very similar, yes."

"But how?"

"They don't use it so much as attract it. It hides their actions from most people, but they can see through it. It's probably how they were able to figure out your and Chat Noir's identities so quickly - as they said, you two are pretty obvious," Tikki giggled. "The suit also helps you to see through the Mist whilst you're Ladybug, but not when you're Marinette. That's why you were able to see the truth during the fight and why the video looked so different - it was a distorted, more acceptable version of reality for your civilian self to handle"

"So this magic, it's like seeing the world through a filter, all the time?" Marinette questioned, trying to understand. She sat down shakily on the lid of the toilet.

"Yes. Although, most Parisians will see more than others, as they've had a high exposure to the weird and wonderful," Tikki explained with a smile. "Most people wouldn't have seen the monster at all, just a pack of stray dogs or something. Instead, the people of Paris saw the monster as an akuma. If you watched the video Alya took again as Ladybug, you'd see the real version of events."

"The Mist is really that strong?" Marinette wondered. Tikki bobbed in agreement.

"Very. It is how Percy and Annabeth's kind - and I suspect others like them - have managed to stay hidden for so long. Even I couldn't detect them until they were very close. Now that I am looking out for them, it will be easier."

"You keep saying that - their kind. What do you mean? What kind?"

Tikki looked worried, and covered her mouth. "I've already said too much. There are ancient laws to protect this knowledge, and it is best for the balance of the universe if the different worlds stay separate, and deal with their own villains."

"But yesterday, I fought one of... their world's monsters!"

"Yes. But don't worry. As a one off, it should be okay."

"So I haven't destroyed the balance of the universe?" Marinette asked, relieved.

"No," Tikki laughed. "But you should probably go meet Chat Noir - remember you agreed to give him the note?"

"Oh, yeah," Marinette rubbed her neck sheepishly. "Oops?"