Well, it could involve a spell gone wrong during some magical experiment. Maybe a misfired charm that had unforeseen consequences on Hermione's body, leading to the pregnancy. The story might then focus on how she copes with this unexpected situation, both physically and emotionally.
In this fanfiction, perhaps it was a dark spell cast by an enemy. The spell was meant to disrupt the Order of the Phoenix, and Hermione was an unfortunate target. Her pregnancy would then be a catalyst for a series of events. The other characters, like Harry and Ron, would have to rally around her to protect her from further harm and figure out a way to reverse the spell.
One possible plot could be that a new, experimental spell in the Hogwarts curriculum backfired on Hermione. Since she's always eager to learn and experiment, she was the first to try it. The spell interacted with some latent magic within her, resulting in the pregnancy. This would create a huge stir in the wizarding world, and the story could explore how the magical community reacts to such an unusual event, as well as Hermione's own journey through this strange experience.
There could be many amateur fanfic authors out there who might have written such a story. It's hard to pinpoint just one. There are numerous fanfiction platforms where people with a creative streak and a love for the Harry Potter universe might have come up with this idea.
One possible plot could be the challenges they face. Maybe Hermione is initially scared and conflicted about the pregnancy as Fenrir is a complex and somewhat dangerous character. Society might not accept their union, so they have to deal with secrecy and the judgment of others.
One possible plot could be that while they are on the run and hiding in the tent, they find unexpected love and a sense of family. Maybe they are forced to rely on each other more than ever, and this closeness leads to a romantic relationship and then the pregnancy. It could be about how they deal with this new situation in the midst of danger and their quest to defeat the Dark forces.
One possible plot could be that they accidentally get exposed to a magical spell or potion that causes the unexpected pregnancy. This then throws their fifth - year studies and their relationships with friends like Ron into chaos as they try to figure out how to deal with it while keeping it a secret from most of Hogwarts.
Perhaps the spell gone wrong could cause them to be trapped in a time - loop. They keep repeating the same day over and over again. As they work together to break the loop, they start to understand each other better. Draco realizes Hermione's intelligence and determination, and Hermione sees that Draco isn't just a mean Slytherin. This could lead to a new - found respect between them.
One possible plot could be that Hermione and Fred start off as friends who gradually develop deeper feelings. Maybe they work together on a project in the wizarding world that brings them closer. Then, an unexpected moment of passion leads to Hermione getting pregnant. The story could then focus on how they deal with the news, including telling their families and friends in the wizarding community, and how they plan for their future together.
Perhaps Hermione tells Draco she's pregnant to get his help in a dangerous situation. Maybe there's a threat to the wizarding world and she believes that Draco, with his family connections and skills, can keep her and the baby safe. So, the plot could revolve around them teaming up against the common threat while dealing with their new situation.
Perhaps it's a result of some dark magic interference. The story could focus on how Harry and Hermione struggle to find a way to reverse it at first. But as time goes on, they start to form an unexpected bond with the unborn child in a magical way. They might face discrimination or suspicion from some in the Hogwarts community who fear the unknown nature of this magical pregnancy, and they have to prove that they can handle it and that it's not a threat to the school.
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.
One possible story could be that it's an alternate universe where Hermione and James are paired. Maybe they fall in love unexpectedly. The pregnancy could bring out a whole new side of their relationship. It could be a story full of challenges as they face the wizarding world's reactions to their union and the upcoming baby.