One interesting plot could be that they are stuck in a magically locked room during a Hogwarts event. They have to put aside their differences to find a way out. Hermione might use her intelligence to analyze the magical locks while Draco, with his knowledge of the Dark Arts (even if he's reformed), could offer different perspectives. They gradually learn to respect each other through this shared struggle.
Initially, they'll be at odds. But when they find themselves in a life - threatening situation while stuck together, like being trapped in a collapsing underground chamber. Draco might save Hermione from a falling rock using his quick reflexes, and Hermione might heal his wounds with her magic. This act of heroism on both parts can break down the barriers between them. They'll then start to rely on each other more, and their relationship will grow from there, gradually becoming closer as they face more and more together.
One possible plot could be that they are stuck in a magically locked room in Hogwarts. They start off bickering as usual, but as time passes, they begin to understand each other better. Draco realizes Hermione's intelligence isn't just for show and Hermione sees that Draco has a softer side beneath his haughty exterior.
Their personalities clash because Hermione is studious, rule - abiding, and values knowledge and fairness. Draco, on the other hand, was initially arrogant and prejudiced. When stuck together, the clash is obvious at first. For example, if they are in a difficult magical puzzle situation, Hermione wants to solve it step - by - step while Draco might want to take shortcuts. But they can also blend. Draco can learn from Hermione's patience and Hermione can see that Draco has his own kind of cunning which can be useful in getting out of the situation.
At first, it might be rocky. Draco, used to his pure - blood superiority, would be a bit resentful of having to share his home and life with Harry. But as time passes, they'd start to see each other's good qualities. Harry's bravery would impress Draco, and Draco's cunning could earn Harry's respect. Eventually, they'd become close friends, always having each other's backs.
The family house - elf could be an important character. It could be the one who takes care of the family home and the kids when Harry and Draco are away on magical business. It could also be a confidant for the children, listening to their problems. And Dumbledore's ghost could make an appearance. He could offer some cryptic advice to Harry and Draco about raising their family in the wizarding world, guiding them to make the right decisions for their family's future.
It could also be the result of a dark wizard's plot. Suppose a dark wizard wants to disrupt the order in Hogwarts. He might use a powerful dark magic to force Hermione, a brilliant and important part of the Gryffindor side, and Snape, who has a complex position in Hogwarts, to be stuck together. This would create chaos and confusion among the students and teachers alike.
In a 'Harry and Draco raised together' fanfiction, it could start with Voldemort being defeated much earlier, and the wizarding world is in a state of rebuilding. The Malfoy family, trying to redeem themselves, takes in Harry. As they grow up, Harry and Draco have a love - hate relationship at first. Draco is jealous of the attention Harry gets, but as they study magic together, they realize they can learn a lot from each other. They might discover new spells by combining the knowledge from different magical families, and this new - found bond could change the entire dynamic of Hogwarts.
The development of the characters can be quite complex. Harry, who is used to having friends like Ron and Hermione, has to adjust to living with someone who was once his enemy. He starts to question his own beliefs about Draco. Draco, too, has to change. Living with Harry makes him confront his own snobbishness. They both might start to pick up on each other's good habits. For instance, Harry could learn some of Draco's organization skills, and Draco could learn Harry's courage in a more personal way, which helps them grow as characters.
One interesting plotline could be them learning to get along despite their past rivalries. For example, they might start to understand each other's insecurities and fears. Another could be them teaming up against a common threat in the wizarding world while living together, which forces them to trust each other. And there could also be a plotline where they discover new magical things together in their shared living space.