One idea could be a time - travel plot where a character from the present goes back in time to the era when the house was first built and has to adapt to the different living conditions. Another could be a mystery - centered plot, like a hidden treasure is rumored to be in the house and the characters search for it.
A really engaging plot might be a competition among the residents of the Adult Lous House. They could be competing for the right to be the 'head' of the house for a year. This would involve various challenges, both physical and mental, and would also test their relationships with each other as they try to outwit and outperform their housemates.
To write a character - driven Adult Lous House fanfic, you need to really understand your characters. Spend time thinking about their flaws and virtues. Let's say you have a character who is overly confident but has a fear of heights. You can use this in the story when they have to climb on the roof to fix something. Their internal struggle will drive the plot as they try to overcome their fear while maintaining their bravado. Also, make sure their relationships with other characters are complex and evolving. This way, the interactions between them will be the main focus of the story.
One idea could be to explore a new mystery in the House of Anubis. Maybe a hidden chamber is discovered that has ancient artifacts and secrets related to Anubis. Another could be to have a character develop a new power or ability that is connected to the Anubis mythology. For example, they can communicate with spirits in the house that hold important information about the past.
One idea could be a behind - the - scenes look at the friendships and rivalries among the stars in the 'house of stars'. For example, exploring how two actors who seem to be friends on the surface are actually competing for the same big role.
One idea could be that the characters discover a hidden room in the Creepypasta House filled with old portraits that seem to come alive at night. Another could be a group of friends getting trapped in the house during a storm and strange noises start coming from different corners, like scratching on the walls. Or perhaps there's a mysterious diary in the house that reveals dark secrets about the previous owners and it seems to have a curse attached to it.
Another plot could involve a love triangle among the Loud siblings' friends. They all end up at the Loud House often, and the love triangle causes some tension. But through various events at the house, like parties or family outings, they start to understand each other better and resolve their differences in a really sweet way.
One plot idea could be that the kids find a way to communicate with the spirit of the house on a deeper level. They learn about its past and find out that it has been misjudged all along. So they set out to change the perception of the house in the neighborhood. This would be a story full of mystery and heartwarming moments.
One idea could be a time - travel plot where a character from the Loud House goes back in time and has to deal with changes in the family's history. Another could be a 'what if' scenario, like what if Lincoln had a different set of sisters. Maybe he could have all older sisters and the story could explore how that dynamic changes things.
In a 'Harry Potter in Slytherin House fanfic', Harry could be sorted into Slytherin due to a prophecy that ties his destiny to the house. He then has to navigate the complex politics of Slytherin. There are power struggles among the students, and Harry finds himself in the middle. He tries to use his unique perspective as someone who was expected to be in Gryffindor to bring about a new era in Slytherin, one that values courage as much as cunning.
One idea could be a story about a house - elf who discovers a hidden magic within themselves that allows them to break free from the traditional bonds of servitude. They could then go on a journey to find other house - elves and teach them this new magic.
Another plot idea is that there's a rift in the House of Hades that is slowly corrupting the place and they have to find the source of it. Along the way, they face their own inner demons. Annabeth might struggle with her insecurities about being smart enough to solve the mystery, while Percy battles with his fear of not being strong enough to protect Annabeth. As they overcome these personal struggles, they also get closer to solving the problem of the rift.