Well, a plot could revolve around Nathalie having a secret past connection to one of the Miraculous holders. This connection could be revealed during a time when the heroes are in a tight spot and Nathalie has to decide whether to help them or stay loyal to Gabriel. Also, a story where Nathalie has a dream or vision about the future of the Miraculous and she tries to change the course of events, which would put her in a moral dilemma between her loyalty to Gabriel and doing what she believes is right for the world.
One idea could be Nathalie's backstory before she became Gabriel's assistant. Maybe she had a different life goal but got drawn into the Agreste world. Another could be Nathalie dealing with her illness in a more in - depth way, like how she copes when Gabriel is not around to support her. Or perhaps a story where Nathalie discovers a new Miraculous that has an unexpected effect on her relationship with Gabriel and Adrien.
A great plot for a Mother Nathalie fanfiction could be Nathalie taking on a more maternal role towards Adrien when Gabriel is away for an extended period. She could start to question Gabriel's methods and motives as she gets closer to Adrien. Additionally, the story could explore Nathalie's relationship with the other characters in the Miraculous Ladybug universe. For example, how she interacts with Marinette's family or the other students at Adrien's school when she has to step in for Gabriel at school events. This could lead to some interesting character development and new story arcs.
One idea could be that they discover a new Miraculous together. They might be on a mission to find it and in the process, their relationship deepens as they face various challenges. For example, they could encounter an enemy who is also after the same Miraculous and they have to work together to outwit them.
It could be Lila. Since she is always causing trouble in the series, in a Nathalie - centered fanfiction, she could target Nathalie as well. Maybe she tries to frame Nathalie for something to get closer to Gabriel or to get rid of Nathalie who she sees as an obstacle to her plans.
One idea could be a story where the Peacock Miraculous has a unique malfunction that causes it to create unexpected akumas. For example, instead of creating the usual villains, it creates akumas that have the power to spread positive emotions but in a chaotic way that still disrupts Paris. Another idea is a fanfiction where the holder of the Peacock Miraculous has to team up with Ladybug and Chat Noir to fight against an ancient evil that is specifically drawn to the power of the Peacock. This could involve exploring the history of the Miraculous and its connection to this new threat.
The plot also matters. It could be a story that takes place within the existing Miraculous Ladybug universe but gives Nathalie a more central role. Maybe she has to make a difficult decision that could change the course of events in the show. Good character development for Nathalie, as well as interactions with other characters like Adrien and Marinette, can make the fanfiction great.
One idea could be Multimouse having to team up with an unexpected ally, like a villain who has a change of heart for a short time. Another could be Multimouse getting lost in an alternate dimension and having to find her way back while facing new challenges.
One idea could be Ladybug and Chat Noir having a heart - to - heart conversation in bed after a particularly tough battle. They could share their fears and insecurities that they usually hide behind their superhero personas.
One idea could be a story where the child of Ladybug and Chat Noir discovers their parents' secret identities by accident. Maybe they find a hidden Miraculous box in the attic and start to figure out what it means.
For a Miraculous Ladybug class fanfiction, a plot about a cursed object in the classroom could be interesting. The object spreads negative energy, causing the students to fight and argue more. Ladybug and Chat Noir suspect that it's an akuma - related thing, but they can't find the akuma. As they investigate, they discover that it's actually an ancient cursed item that was accidentally brought into the class. They have to find a way to break the curse without revealing their identities, and also deal with the fact that their classmates' relationships are falling apart because of the curse.
Maybe there's a werewolf akuma. Hawkmoth takes advantage of an already existing werewolf in the city and akumatizes it. This werewolf - akuma has enhanced powers and is causing chaos. Ladybug and Chat Noir must figure out how to defeat it. They might need to discover the true identity of the werewolf to break the akuma's hold. It could be a person who was bitten recently and is struggling to control their new form.
Another plot could be that a crime wave hits Paris, and all the evidence points to Chat Noir as the perpetrator. Ladybug is torn between believing in her partner and the mounting evidence against him. She has to dig deeper into the case to find the real criminal who is framing Chat Noir and clear his name.