A really interesting twist could be that Hermione's presence in Middle - earth is actually a key part of an ancient prophecy that no one knew about. As Aragorn's sister, she might be the one to unlock some great power or knowledge that is crucial for the victory over evil. This would make her a central figure in the story, not just as Aragorn's sister but as a key player in the fate of Middle - earth.
Maybe Hermione discovers that her family in the wizarding world was cursed by an evil force long ago, and this curse has something to do with Aragorn's family too. As she and Aragorn try to figure out the curse, they uncover secrets about both their worlds that could change everything. This would lead to a lot of mystery and adventure as they race against time to break the curse and save both Middle - earth and the wizarding world.
One interesting plot twist could be when Hermione discovers her true heritage and has to face the fact that she's related to the Malfoys. It completely changes her relationship with Draco. Instead of being enemies, they have to figure out how to be siblings in a world where their families have such different values.
Well, a really cool plot twist might be that Snape starts to have his own thoughts influenced by Hermione's. Since he can hear her so often, her way of thinking begins to seep into his mind. Maybe he starts to question some of his long - held beliefs about the Gryffindors or about magic in general. Also, it could be that Hermione discovers a way to communicate back to Snape through her thoughts, like a two - way mental communication, and they start to form a secret alliance that no one else in Hogwarts suspects.
One interesting plot twist could be that Hermione and Harry discover their relation much later in their Hogwarts years. Maybe they've always had a special bond but just attributed it to their friendship. Another could be that their shared heritage gives them unique magical abilities that no one else has, like a combined spell -casting power that can defeat the darkest of dark wizards.
A really interesting plot could be a time - travel scenario. Aragorn travels to the future and ends up in the wizarding world where he meets Hermione. She teaches him about modern magic and they go back to Middle - earth together to use this new knowledge against an ancient evil. Or perhaps there's a prophecy that involves both of them, and they must figure out their roles in fulfilling it, which takes them on a journey across both their worlds, facing various challenges along the way.
One interesting plot twist could be that despite being siblings, they are sorted into different houses, and this causes a rift in their relationship initially. But as the story progresses, they find common ground in their magical abilities and family secrets.
Perhaps Hermione discovers she has some long - lost connection to Aragorn's family. In the fanfiction, she could bring her knowledge of magic to Middle - earth. For example, she could use her healing spells to tend to Aragorn's wounded soldiers, and as they work together more closely, they come to recognize each other as family.
Perhaps a plot twist could be that Draco is under the influence of a dark spell when he kidnaps Hermione, and as she tries to break the spell, she uncovers a conspiracy within the wizarding world. Or it could be that the kidnapping is a ruse set up by Hermione herself to infiltrate the Slytherin group, but Draco doesn't know it and things spiral out of control.
One possible plot twist could be that Hermione discovers a hidden power within herself that is not in the original books. For example, she might find out she has a special connection to an ancient magic that only warriors possess. This could change her role in the wizarding world completely and lead her on a new adventure to master this power.
One possible plot twist could be that Hermione is secretly related to a powerful and ancient wizarding family that has been in hiding. This would add a whole new layer of mystery and power to her character.
A plot twist could be that the Triwizard Cup is actually a portal to a different dimension, and Harry and Hermione accidentally get transported there during the final task. They then have to find a way back while dealing with strange creatures and magic in this new dimension.