The relationship between Ladybug and Chat Noir could deepen into a more mature partnership. They might start to rely on each other not just as superheroes but also as friends who truly understand each other's strengths and weaknesses. Marinette could also become more confident in her relationship with Adrien, and their romantic feelings might become more open in the future setting of the fanfiction.
One idea could be that Ladybug and Chat Noir face a villain who can manipulate time in the future. This would force them to not only fight in the present but also find a way to prevent the villain from causing chaos in the future. Another plot could involve a new Miraculous holder from the future coming back to help them in their present battles, bringing with them new powers and a different perspective on their fight against evil.
Title: 'Miraculous: Into the Uncertain Future'. The story could start with an event that shakes the very foundation of the Miraculous world. Maybe Master Fu is gone, and Ladybug and Chat Noir have to figure out everything on their own. They encounter strange new Miraculous holders who may or may not be on their side. With every decision they make, the future of the city and the Miraculous lore becomes more and more uncertain.
Maybe a new character from another country comes to Paris. This character has a Miraculous that has powers related to nature. Their role would be to bring a new element to the team. They could use their powers to heal the damaged parts of Paris that were affected by Hawkmoth's attacks, and also help in battles by using nature - based defenses like thick vines to trap villains.
Well, it could be about Ladybug and Chat Noir finally revealing their identities to each other and having to deal with the consequences. Maybe they face a new, more powerful villain that is a threat to all of Paris and they have to use their combined powers in new ways.
The main plot could be about a new threat emerging that is far more powerful than any they've faced before. For example, an ancient evil that was sealed away long ago is now breaking free. With the Miraculous holders being young and inexperienced in dealing with such a powerful foe, the future of Paris looks very uncertain. They have to quickly learn new powers and strategies, all while trying to keep their identities secret from their friends and family who are also in danger.
In a 'Watching the Future' Miraculous Ladybug fanfiction, Ladybug and Chat Noir might see their future selves facing a super - powerful villain. They could then start training harder in the present to be better prepared.
Another theme could be legacy. Since it's about the future, the idea of leaving a positive legacy as superheroes could be explored. They might be mentoring new heroes, passing on their values and knowledge about the Miraculous.
It could involve exciting new Miraculous powers for Ladybug and Chat Noir. Maybe in this 'Peak Future' they have mastered their existing powers to an extreme level, like being able to combine their Lucky Charm and Cataclysm in a more powerful and unique way.
A new villain could be a former Miraculous holder who turned evil due to some misfortune. Maybe they felt betrayed by the Order of the Miraculous and now seek revenge. Another possibility is an alien entity that is attracted to the power of the Miraculouses and wants to use them to conquer Earth.