In the fanfiction, it could be that they are both on a mission together. Harry trusts Daphne completely, but she is blackmailed into betraying him. The blackmailer has something on Daphne's family, so she gives Harry false information that leads him into a dangerous situation. Harry then discovers the truth and has to decide whether to save Daphne when she realizes her mistake.
Perhaps Harry and Daphne are part of a secret organization in the fanfiction. Daphne betrays Harry by revealing his identity to the enemy for some personal gain, like protecting her family from a threat the enemy made. Then Harry has to deal with the consequences of her betrayal and also figure out if he can forgive her.
One possible plotline could be them teaming up to solve a mystery within Hogwarts that the teachers are unable to figure out. Maybe it's about a hidden chamber or a strange magical occurrence. Another could be Daphne helping Harry deal with his PTSD from his encounters with Voldemort. They could also form a study group together and end up learning new and rare magics.
One possible plotline could be that some of the former Death Eaters who were pardoned as part of the post - war reconciliation secretly plot against Harry. They might spread false rumors about him misusing his power or being a threat to the wizarding world again. Another could be that some of his own friends turn on him out of jealousy. Maybe they feel overshadowed by Harry's continued fame and hero status and start to believe the lies being spread about him.
One possible plotline could be that they fall in love gradually. Maybe they start as friends who bond over shared interests or experiences in the wizarding world. As their relationship deepens, they decide to keep it a secret to avoid unwanted attention or interference. Another aspect could be how they deal with their families. Harry has his own complex family history and Daphne might have expectations from her family. They would need to navigate these challenges while keeping their marriage under wraps.
In another scenario, Daphne could be in some sort of trouble, and Harry, being the hero he is, decides to help her. It could be related to her family's dark past catching up with her or a dangerous magical artifact she has come across. As he helps her out of the situation, their bond deepens. Harry then has to decide whether his feelings for her are just a result of the rescue situation or something more profound.
It could be that Daphne has a personal connection to Harry that she's not aware of until she starts investigating the strange magical disturbances around the Dursleys' place. Once she realizes it's Harry in trouble, she enlists the help of her friends or some sympathetic wizards to break Harry free. She might also face some challenges along the way, like dealing with the Dursleys' resistance or the Ministry of Magic's rules about interfering in Muggle affairs.
One possible plotline could be that Ron and Hermione are influenced by dark magic or a powerful enemy who manipulates them into betraying Harry. For example, they might be under the Imperius Curse. Another could be that they misunderstand Harry's actions or intentions, leading them to believe he has gone to the dark side, so they turn against him in an attempt to 'save' the wizarding world. Maybe they are jealous of Harry's fame and power growing too much, and this envy festers until they decide to betray him.
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.