In this fanfiction, Marinette and Tikki could be transported to an alternate version of Paris. Here, everything is different, and they have to find a way back. Marinette uses her wits and Tikki's knowledge to navigate this strange new world. They meet different versions of their friends and enemies, and through their adventures, they learn more about themselves and their relationship.
One possible fanfiction could be about Marinette's daily life with Tikki. For example, Marinette could be having a tough day at school, getting bullied by Chloe. Tikki, being her kwami, tries to cheer her up by suggesting they make some special macarons. They then spend the evening in Marinette's room, sharing stories and laughing, which helps Marinette forget about her bad day.
She could be in the hospital because of a bad fall during a chase in her Ladybug form. Her classmates might start a fundraising campaign to help with her medical bills. And Chat Noir could be secretly visiting her at night, leaving little gifts by her bedside.
She could have been kidnapped by a new villain who wants to use her skills as a fashion designer for some evil purpose. Since Marinette is so talented, this villain might think she can create special costumes or items for their evil plans.
Perhaps there's a beach fashion show in the fanfiction. Marinette enters wearing her bikini and wows everyone with her unique style. It could also be a moment where she catches the eye of Adrien, who is there to support his friends in the show.
Maybe she was framed by an Akuma - influenced villain. In the 'Miraculous Ladybug' world, this is quite likely. Her arrest could be part of a larger scheme to distract Ladybug and Chat Noir. So, Ladybug might have to balance her superhero duties with clearing Marinette's name, which would be a really interesting plot twist.
She might receive a mysterious gift that has some connection to her Ladybug identity. For example, it could be an ancient book about the Miraculous that has been lost for centuries. This gift could lead her on a new adventure to uncover more about the history of the Miraculous and her role as Ladybug.
In a Miraculous Ladybug sleepover fanfiction, the characters might have a lot of fun. They could play games like truth or dare, which could lead to some interesting revelations. For example, Marinette might accidentally let slip some of her feelings for Adrien.
Well, they could get into all sorts of mischief. Maybe they decide to play a prank on their holders. Tikki could use her positive energy to create an illusion of a delicious macaron that Plagg can't resist, but when he tries to eat it, it disappears. And then Plagg could use his Cataclysm to create little harmless 'disasters' like making a small pile of papers look like they've been completely destroyed, just to make Tikki gasp in surprise.
One possible plot could be that Marinette enters a singing competition. She is super nervous at first, but as she starts singing, she gains confidence. Her song could be about her journey as Ladybug, without revealing her identity of course. And her performance might attract the attention of a new villain who wants to use her voice for their evil plans.
They could be paired up for a hero - training exercise. Since Marinette is Ladybug and Chloe has been Queen Bee in the past. They have to learn to work as a team. This forces them to put aside their differences. They might start to see each other in a new light. For instance, Marinette could learn that Chloe has a lot of knowledge about Parisian high society that could be useful in fighting villains. And Chloe could see Marinette's strategic thinking as Ladybug.