Another plot could involve them facing a common enemy at Hogwarts. Since they are siblings, they would have to work together, combining their unique skills and knowledge. For example, Harry's courage and Daphne's intelligence in potions or other areas of magic could be used to outwit the enemy. They might also have to deal with the social implications of being siblings in different Hogwarts houses, which could lead to some interesting character development and interactions with their peers.
One interesting plotline could be them discovering a hidden family secret together. Maybe they find out that their family has a long - lost magical heirloom that holds great power. They would then embark on a journey to learn more about it and protect it from those who would misuse it.
Their relationship could be one of mutual protection. Harry, with his heroic nature, would always be ready to defend Daphne. And Daphne, being intelligent and resourceful, could offer her own kind of support to Harry, like helping him with his studies or providing advice in tricky situations.
One interesting plotline could be how Harry and Daphne initially react to the marriage contract. Maybe Harry is hesitant at first, but as he gets to know Daphne better, he starts to see the potential in their relationship. Another could be the challenges they face from their families and society due to the contract.
One interesting plotline could be their exploration of the secrets within the House of Black. Maybe they discover long - lost magic or family heirlooms. Another could be their relationship development against the backdrop of the complex Black family politics.
Another plot could involve Daphne Greengrass being a secret admirer of Harry Potter from afar. As the story progresses, she gradually reveals her feelings and they start to bond over their shared experiences of the wizarding world, like dealing with the expectations of their pure - blood families.
One interesting plotline could be how they navigate the wizarding society's reactions. Since Daphne is from a different social circle than Harry, there might be challenges in how they are perceived together. For example, Daphne's pure - blood family might have certain expectations that contrast with Harry's more inclusive views. Another plotline could involve them using their combined magical skills to solve mysteries in the wizarding world. Harry's combat and survival skills along with Daphne's knowledge of potions and magic theory could make them a formidable team.
One possible plotline could be that they meet in the library while searching for a rare book. Harry might be looking for something to help him with a difficult class assignment, and Daphne could be researching dark magic for a different reason. They start off as rivals in this search but gradually develop a mutual respect and then friendship that could potentially turn into something more.
One interesting plotline could be them meeting in a secret place in Hogwarts, like the Room of Requirement. They start off as acquaintances but gradually fall in love as they discover shared interests, like a love for ancient magic spells.
A plotline where Harry, Daphne, and Astoria are all part of a secret club in Hogwarts that is dedicated to uncovering the long - lost magic of the founders. They go on adventures in the castle, searching for hidden chambers and ancient spells. This would bring out their individual personalities and how they interact with each other. For example, Harry's bravery, Daphne's intelligence, and Astoria's creativity could all play important roles in their discoveries.
One possible plotline could be Harry and Daphne exploring the wizarding world together, like visiting hidden magical places. Another could be them facing some kind of mystery at Hogwarts that only they can solve through their combined skills.
A common plotline is that Daphne saves Harry from a dark magic attack. For example, she might notice a cursed object meant for Harry and intervenes just in time.