One possible plot twist could be that Hermione discovers a hidden side of Dumbledore. Maybe she finds out about a secret mission he was on long ago that has consequences in the present. For example, she could stumble upon a hidden prophecy related to Dumbledore that changes the way she views him and the entire wizarding world's future.
A plot twist could be that Dumbledore is not really Dumbledore. Hermione starts to notice some strange behavior from him. As she follows him, she realizes that he has been impersonated by a powerful dark wizard who wants to use Dumbledore's reputation to gain access to powerful magical artifacts. Hermione then has to find a way to expose the imposter without getting caught.
Hermione's character could develop by becoming more confident in her own instincts. Following Dumbledore, she may start to trust her own judgment more as she observes his actions. For instance, if she disagrees with one of his decisions, she might be more assertive in voicing her opinion, which is a growth from her more deferential nature in the original books.
She might be involved in tasks like researching ancient magic. Dumbledore, being very knowledgeable, could send Hermione to dig into old books and scrolls in the library to find information about a particular dark magic threat or a powerful spell that could be used for good. For example, if there's a new dark wizard on the rise, he might ask Hermione to look for any historical records of how similar threats were dealt with in the past.
She becomes more confident in her decision - making. Following Dumbledore's orders, she often has to make quick and important choices. This forces her to trust her instincts more, which in turn makes her more self - assured. For instance, when she has to decide whether to enter a dangerous area to retrieve an important item for Dumbledore, she learns to weigh the risks and benefits on her own and act accordingly.
Well, one possible plot twist could be that the father of Hermione's baby is not who everyone expects. Maybe it's a character who has been secretly in love with her all along. Another could be that there are some magical complications during the pregnancy that put Hermione's life at risk. And the baby could have some extraordinary magical powers even before it's born.
Well, a plot twist might be that the Marriage Law is actually part of a dark wizard's plan. Hermione and Charlie then find themselves in the middle of a much larger conspiracy. They might have to use their unique skills - Hermione's intelligence and Charlie's dragon - handling knowledge - to expose the plot and in the process, their relationship could either strengthen or face challenges. Also, perhaps there are ancient magic rules related to such marriages that they need to figure out.
Perhaps Snape and Hermione were secretly working on a time - traveling potion project. Due to some unforeseen consequences of time manipulation, Hermione ended up pregnant. It could also be that a powerful magical artifact they were studying had some sort of fertility - enhancing effect that they didn't anticipate at first.
One possible plot twist could be that at first, Hermione and Severus despise each other due to their past differences. For example, Severus has always been rather cold towards Gryffindors, and Hermione is a proud Gryffindor. But as they are forced to spend time together because of the arranged marriage, they start to discover each other's hidden depths. Hermione might find Severus's intelligence and his complex past with Lily fascinating. And Severus could come to respect Hermione's quick wit and thirst for knowledge. Another plot twist could be that there is some external force trying to break up the arranged marriage. Maybe some dark wizards see it as a threat to their plans, or there are those in the wizarding world who oppose the union of a Muggle - born like Hermione and a former Death Eater like Severus.
One possible plot twist could be that Hermione is actually from a pure - blood family but has been hiding it for some reason. Maybe she wants to distance herself from the pure - blood elitism in the wizarding world. Another could be that she fakes her blood status to gain access to certain resources or information that are restricted to particular blood status groups. It could also lead to a situation where her friends find out and there is a rift in their relationships until they understand her motives.
One idea could be a time - travel plot where Hermione goes back in time and teams up with a young Dumbledore to solve a mystery that has implications for the future of Hogwarts. Another could be a story where Dumbledore entrusts Hermione with a special mission that no one else in the wizarding world can handle due to her unique skills and knowledge. Maybe a plot where Hermione discovers a long - lost spell in the Hogwarts library that was created by Dumbledore in his youth, and she has to figure out how to use it to save the school from a new dark threat.
One possible plot could be that Hermione discovers a hidden family secret that reveals she is Dumbledore's sister. This leads to her having access to new knowledge and powers that Dumbledore left for her, which she uses to fight a new dark force in the wizarding world.