The plot might involve their family backstory. Maybe their parents were involved in some secret magical research that put their family in danger. As siblings, Harry and Luna could be on a quest to uncover the truth about their family's past while also dealing with the normal Hogwarts drama like exams, Quidditch, and the threat of the Dark Arts. They could also have a special bond that allows them to communicate telepathically or something similar, which would add an interesting twist to the story.
One plot could be that Harry has to defend his ownership of the Luna fanfiction against those who want to claim it for themselves. This could lead to a series of adventures and magical battles within the fanfiction world.
It could be about Harry and Luna going on a secret adventure in the Forbidden Forest. Maybe they discover a new magical creature that no one else knows about.
Perhaps in a fanfiction, Harry is on a journey to find a sense of normalcy after all the chaos. Luna, being as unique as she is, shows him a different way of looking at life. They bond over their experiences with the Cursed Vaults and the fight against Voldemort. Eventually, they decide to get married and their wedding is a blend of both their personalities - full of strange creatures as decorations and the most delicious, magical food.
There probably is. The Harry Potter fandom is vast and diverse. Writers might explore this relationship in fanfictions for various reasons. Maybe they want to give Luna a closer connection to the main story through Harry, or perhaps they just like the idea of changing the family dynamics in the wizarding world. Check the major fanfic platforms and use relevant tags to look for it.
Well, perhaps they move to Forks for a new start. Maybe they are intrigued by the different atmosphere there compared to their own magical world. They could explore the non - magical side of life, make new friends, and Luna might find some really interesting natural phenomena in Forks to study.
Well, perhaps they run away to escape the chaos at Hogwarts. Maybe they've discovered a dark secret within the school that puts their lives in danger. So they decide to flee and find a hidden place in the Forbidden Forest to stay safe.
In the fanfiction, Luna might be lost in a time - loop created by a malfunctioning time - turner. Hermione realizes what has happened due to her familiarity with time - turner magic. Harry goes with her to enter the time - loop. Inside, they face various challenges from different time periods. They find Luna, who has been trying to break the loop on her own. The three of them then work together. Hermione figures out the correct sequence of spells, Harry provides the necessary distraction to the time - loop's guardians, and Luna uses her natural connection to magic to help Hermione complete the spell that breaks the loop.
The plot might start with the announcement of the marriage law which forces Harry and Luna into a situation. Then they gradually get to know each other better in a new way. Luna's unique view of the wizarding world might influence Harry a great deal. They could also be involved in some sort of mystery related to the marriage law, like uncovering some hidden clauses or a conspiracy behind it. Their relationship would grow stronger as they face these things together.
One possible plot could be that the wizarding world is in a state of upheaval due to Harry's transformation into Lucifer. Luna, as a prophet, has visions of a future where either Harry destroys everything or redeems himself. The story could follow their journey as Harry battles his newfound dark nature, and Luna uses her prophetic abilities to try and influence his decisions. There could be other characters who either fear or try to use Harry's new power, adding more layers to the plot.
Well, it could be about Luna having magical adventures with Harry while being his pet. Maybe she has special powers even as a pet that help Harry in his battles against the dark forces.