In some fanfictions, a great plot twist is that their twin connection is what draws Voldemort to target Hermione as well. This changes the whole dynamic of the story as Hermione becomes an even more central target. It also means that she has to deal with the same prophecy that Harry does, adding a new layer of complexity to her character arc.
A really cool plot twist might be that their twin -ship was hidden by some powerful magic for their protection. But as they grow older and more powerful, the magic starts to fade. This discovery then leads them on a quest to find out who hid their relationship and why. Along the way, they uncover secrets about their parents and the wizarding world that were long buried.
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.
One plot idea could be that Hermione and Harry discover their twin connection early on. They might use their combined intelligence and magic to solve mysteries even faster at Hogwarts. For example, in dealing with the Philosopher's Stone mystery, they could come up with a more elaborate plan together to protect it from Voldemort. Another idea is that their bond affects the relationships with their friends. Ron might initially be a bit jealous of their closeness but then come to appreciate how their twin connection benefits the whole group.
A possible plot twist could be that Hermione is a half - veela. This is not related to being a Muggleborn at all. The fanfiction could show how her veela heritage affects her magic and her relationships at Hogwarts. For example, it might make her more alluring and powerful in certain types of magic, like charms. This would completely change the way her character is typically portrayed in the original stories where she was thought to be a Muggleborn.
One interesting plot twist could be that Hermione, as a Gryffindor in the original series, starts to question the values of her own house because of her newfound admiration for Slytherin. Maybe she discovers a long - lost family connection to a Slytherin family, which makes her more empathetic towards their ways. Another could be that she uses Slytherin - like cunning to solve a problem that Gryffindor bravado couldn't handle, causing a rift between her and some of her Gryffindor friends.
One interesting plot twist could be that Hermione's real family is a powerful wizarding dynasty in hiding. For example, they might have been in hiding from a dark wizard who was after their unique magical abilities. Another could be that she was adopted to protect her from a prophecy related to her future powers. Maybe she discovers that she has a connection to an ancient magical artifact that only her real family knew about, and this discovery changes her whole perspective on her identity and place in the wizarding world.
There's a fanfic where the forgotten twin is raised in a different part of the wizarding world. As the story unfolds, they end up at Hogwarts and there are a lot of secrets and mysteries surrounding their identity. It's really interesting to see how they interact with Harry and Hermione, especially when old family secrets start to surface.
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.
In some of these fanfictions, a great plot twist is when Hermione's switch to Slytherin causes a rift among her old Gryffindor friends. However, this rift actually leads to a deeper understanding between the houses in the long run. She might also start to question the values she was taught in Gryffindor and find that Slytherin has some values, like ambition in a positive sense, that she can really embrace. And there could be a plot where she has to use her new - found Slytherin knowledge to save Hogwarts from a threat that Gryffindor - centered magic couldn't handle.
Well, sometimes in these fanfictions, a plot twist is that the Prewett twins are actually under a hidden curse. Hermione, being the brilliant witch she is, has to figure out how to break it. And it turns out that the curse is related to an ancient magic that has been long forgotten. This leads to a whole adventure where they have to search for clues in the Forbidden Forest and old wizarding libraries.
Maybe the twin sister has a different type of magic than Harry. For example, while Harry is known for his connection to Voldemort and his Parseltongue ability, she could have the power of prophecy. She starts having strange dreams about future events in the wizarding world that are crucial to saving it from new threats, and she has to figure out how to interpret and act on these prophecies.
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.