The dark side of her... {Completed} {Editing}

Who was it then?

As Chat Noir raced to the Agréste mansion and let her transformation loose, she thought about the last time she was in this room.

*flashback*
Ladybug entered the guest room and saw Adrien waiting for her. There was a picnic blanket with two plates. On the plates were Marinette's favourite sandwiches. Ham and cheese! There was a chocolate cake next to it. That was their third date (before they had their break).
*end of flashback*

A few tears rolled down her cheek but she quickly wiped them away. It broke her heart to see her whole world has changed. She has a different dad and no mum at all.

"Mari, who could it be?" asked Plagg.
"I'm not sure Plagg. I mean, if it wasn't Hawkmoth, then Nightmare Designer was working for someone else!" she sighed.
"Knock knock," said Adrien. Plagg's eyes widened and he quickly hid behind Marinette's hat.

"Adrien... what brings you here... big bro?" she asked while smiling awkwardly.
"What was that black thing that you moved behind your hat?" he asked.
"Oh this, a toy I found in the streets a few years ago. It turns out he's called a kwami plushie toy and I named him Plagg," she lied, holding him up.
"Does it do anything?" he asked.
"Hm, no!" she laughed.

Sudden flashbacks came to him. But ones he did not recognise.
"Why do I recognise 'him'?" he asked.
"Umm... maybe you've seen him in here a couple of times?" she suggested, getting extremely worried.
"No. I see him in my dreams when I'm Chat Noir," he said, walking towards her.
"Maybe you've seen him a few times that you got paranoid that he appeared in your dreams," she suggested.
"No, that's not it at all," he smirked and walked towards her again. She could feel him breathing on her.

A sudden urge came to her so she followed it. She slapped him around the face super hard.
"Ow princess! What was that for?" he whined.
"Am I Marinette Agréste?" she asked.
"No, but it has a nice ring to it. Don't you think?" he smirked, holding his hand to his cheek.
"Adrien!" she squealed and jumped into his arms.
"Wow! I haven't been gone long! Hold on, why are we here? We were with Nightmare Designer!" he exclaimed and Plagg came up to hug his cheek.
"Long story. Anyway, do you remember anything about Nightmare Designer? Who did she work with? Where has she taken Tikki?" asked Marinette.
"No not really. Just my the words 'I'm sorry bugaboo', why?" he asked.

His hand was starting to glow.
"M'lady, care to explain what this is?" asked Adrien holding it out.
"Yeah probably. Get out!" she instructed.
"Alright. Goodnight princess," he winked.

He walked outside and she shut the door behind him.
"And now he's my big brother again," she sighed.
"It's ok Mari. At least we know how to get him back," encouraged Plagg.
"Yeah but what if it only works the once!" she complained.
"Then we have a situation. But one things for sure," he said.
"What?"
"He was of no help to find out who had Tikki!"

Ok guys so some of you have been wondering how we got to an alternate universe yet we just had Chat Blanc. Well, it's like a few days later. I don't think that helped you but I did try. Shoutout to captainswanatonce