A possible plot could revolve around a magical prophecy that states only the union of Harry and Hermione can save the wizarding world from a new, unknown threat. At first, they are both skeptical but as they start to investigate the prophecy together, they begin to understand each other on a deeper level. They might face opposition from some pure - blood families who don't believe in their union. As they grow closer, they also have to balance their individual goals and dreams with the expectations of the wizarding world regarding their betrothal.
One interesting plot idea could be how they initially react to the betrothal. Maybe Hermione is more accepting as she sees it as a way to strengthen the wizarding world, while Harry is more hesitant. Another idea is how they deal with Ron's reaction, since he has feelings for Hermione. They might have to work through their friendship with Ron while also coming to terms with their new relationship status.
Well, a great plot could be set in a time where Voldemort has been defeated but the wizarding world is still in chaos. The betrothal between Harry and Hermione could be seen as a symbol of hope and unity. They could embark on a journey to different wizarding communities to promote their union and in the process, discover new magic and face old enemies who want to disrupt their relationship. Also, there could be a sub - plot about how they learn to love each other, as they were just friends before.
One plot idea could be that it's a magical mishap. Maybe a spell gone wrong during an experiment causes Harry to become pregnant. Another could be a prophecy related to a new kind of magic that can only be carried out through his pregnancy. It could also be a situation where a powerful dark magic is trying to use Harry's unborn child for some evil purpose.
One idea could be a time - travel fanfic where Harry and Hermione go back in time to change certain events in the wizarding world's history. This could lead to all sorts of interesting plot twists.
One idea could be a story where baby Harry and Hermione are magically transported to a different time or place. They could be in a magical forest full of strange creatures that they have to befriend in order to find their way back. Another plot could involve them as babies having a special connection that allows them to communicate without speaking. This could lead to them solving small mysteries in Hogwarts even at a very young age. A third idea might be that they are found by a group of magical beings who don't know who they are and raise them with different magical traditions, and later they discover their true identities.
One plot idea could be that Harry discovers unique magical creatures that exist only in space. For example, there could be a species of floating, star - like creatures that can communicate through light pulses. Another idea is that he has to learn to control his magic in zero - gravity, which presents a whole new set of challenges compared to on Earth. Maybe he also forms an alliance with alien races who are also magically inclined and together they fight against a common dark force that threatens both the wizarding world and the galaxies.
Perhaps the monster has a vendetta against certain wizarding families, and as Harry grows up under its care, he is caught in the middle of this conflict. He has to decide whether to side with the monster or try to find a way to reconcile the differences. This could lead to a whole new set of adventures and challenges for Harry.
There could be a 'Harry Potter betrothed fanfic' where Harry is betrothed to a new character created by the author. This new character might be from a different magical family. The story could then revolve around Harry learning about this new family's traditions and trying to blend them with his own life at Hogwarts.
One idea could be that they initially resist the betrothal. Harry is suspicious of Daphne because of her Slytherin heritage, and Daphne thinks Harry is just a fame - seeking Gryffindor. But as they are forced to spend time together for various magical tasks assigned by their families, they start to see each other's true natures and gradually fall in love.
A great plot could be that they discover they are twins later in their Hogwarts years. This revelation could cause a stir in the wizarding world. They might then start to explore their family history together, finding out secrets about their parents that were previously unknown. Maybe they find out that their parents had some special mission that they now need to continue as twins.
Well, a plot could involve Hermione being influenced by a powerful dark magic item. This item warps her mind and makes her see Harry as a threat to the wizarding world. So, she betrays him by revealing his secrets to his enemies. Or perhaps she gets jealous of Harry's popularity and power and that leads to her betrayal in a moment of weakness.
One idea could be a time - travel plot where Hermione and Malfoy are sent back in time together and have to rely on each other to get back, while Harry is somehow involved in the events that led to their time - travel. Another could be a story where they are all part of a secret magical project that forces them to work together despite their differences. Malfoy might have some unique knowledge that Hermione respects, and Harry could be the mediator between their clashing personalities.