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.
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.
She could gain new powers. For example, if she got the Fox Miraculous instead of the Ladybug Miraculous, she'd have the power of illusion. This would change the way she battles villains completely. She could create false images to mislead them, rather than using the more direct combat approach of the Ladybug Miraculous.
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.
Another thing that could occur is that their relationship dynamic would completely change. Instead of the usual cat - and - mouse game between Adrien and Marinette (where Marinette is shy around Adrien), Adrien could be more open and direct with her. Since he knows her big secret, he might feel a stronger connection to her and try to get closer in a different way than before.
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.
Perhaps the ladybug is a messenger from another world. When it enters the classroom, it starts to communicate with the teacher through some sort of telepathy. The teacher then has to figure out how to convey the ladybug's message to the students. This could lead to an adventure where the students and the teacher have to follow the ladybug's instructions to save their school or even the whole world.
Maybe Marinette (as Ladybug) gets a truth about Adrien (Chat Noir) that she has been dying to know. For example, if he has ever had feelings for her outside of their superhero personas. This would make for an interesting plot twist, as it could either bring them closer together or create some awkwardness between them depending on his answer.
Well, he might be really surprised at first. Then he could start to see Marinette in a whole new light. Maybe he'll become more interested in her as a person, not just as a friend.
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 fanfiction scenario where Marinette gets akumatized, it's a really fascinating concept. Marinette is known for her strong will and positive attitude, but if she's akumatized, all that could be flipped. Her akumatized form might be influenced by her repressed emotions, such as her jealousy over Lila's lies being believed so easily. Her akuma - powered actions could start to cause chaos in Paris. And it would be a great opportunity for the other characters to step up and try to save her, not just as Ladybug, but as Marinette. There could be a lot of self - discovery and character growth for everyone involved as they face this new and unexpected threat.