The fanfiction could center around a new student who is secretly a villain in disguise. They try to disrupt the school play which is about the Miraculous Ladybug and Chat Noir's adventures. Ladybug and Chat Noir have to figure out who the new student really is and stop their evil plan before the play is ruined.
Well, in a Miraculous Ladybug school trip fanfiction, there could be a lot of exciting things. Maybe Ladybug and Chat Noir have to protect their classmates from an akumatized villain during the trip. For example, the villain could target the school bus or the destination they are visiting.
Well, Ladybug and Chat Noir could show up at the school dance in their civilian forms. Maybe Adrien and Marinette would be too shy to ask each other to dance at first. But then, some akuma - related chaos could start near the school, and they'd have to find a way to transform and save the day without revealing their identities to their classmates.
The main characters would definitely be Marinette and Adrien. Marinette, who is Ladybug, would be a central figure as she tries to balance her normal school life during the trip with her superhero duties. And Adrien, as Chat Noir, would be there to support her and also have his own storylines, like dealing with his overbearing father's restrictions even during the trip.
Perhaps an outside force, like an alien entity, could invade the hero school. This entity could be attracted by the powerful Miraculous energy. It would be a very different kind of villain as it has no concept of the human values that the heroes at the school uphold, and it would take all of their combined skills to defeat it.
Another plot could involve a school project where the students have to work in pairs. Marinette and Adrien get paired up, but there are complications due to their superhero identities. For example, they keep having to sneak away during the project to deal with akuma attacks, which makes their partner suspicious.
Once upon a time, in the deep blue sea, there was a miraculous mermaid named Marina. She had a special power - the ability to heal any wound with a touch of her pearl - like scales. One day, a human sailor named Leo fell overboard during a storm. Marina found him and used her power to save his life. Leo was amazed by her beauty and kindness. He visited the sea often after that, and they became friends. Their friendship grew into love, but they knew there were many obstacles. Marina couldn't stay on land for long, and Leo couldn't live in the sea. However, with the power of their miraculous bond, they found a way to be together. They discovered an ancient magic that allowed Marina to transform into a human for short periods, and Leo learned to swim and hold his breath for longer. Their love story became a legend in both the human and mermaid worlds.
One idea could be a new student arriving at the hero school who has a mysterious power that even the Miraculous Ladybug and Chat Noir don't understand at first. This could lead to a series of adventures as they try to figure out the power and whether it's a threat or an ally.
Well, a great plot for a Miraculous Ladybug school sleepover fanfiction could be that there's a mysterious object found in the school during the sleepover. It seems to have some sort of power related to the Miraculous. This object causes strange things to happen, like swapping the personalities of some of the students. Ladybug and Chat Noir suspect that it might be a trap set by an unknown enemy. They have to find a way to reverse the effects and discover the origin of the object. Or, perhaps there's a sleepover - themed akuma. For example, an akumatized student who is angry because they didn't get invited to the sleepover. Ladybug and Chat Noir have to defeat this akuma while also trying to keep the sleepover fun for the other students.