One possible plot could be that Draco, for some reason, becomes Hermione's servant. Maybe it's part of a magical pact or a punishment from the wizarding world. Draco, being used to his pure - blood superiority, would initially resist but gradually learn to respect Hermione's intelligence and kindness. They could then go on adventures together, facing various magical threats and learning more about each other's true natures.
In a fanfiction like this, the plot might revolve around Hermione using Draco as a servant to gain access to some secret Malfoy family knowledge. Draco, in turn, tries to outwit her but finds himself in situations where he has to rely on Hermione's skills. It could lead to a begrudging friendship and a whole new perspective for both characters on the Gryffindor - Slytherin divide.
Perhaps the fanfiction starts with Hermione being given Draco as a servant as a result of a magical bet. Draco is horrified at first, but as he serves Hermione, he discovers her strong will and her determination to make the wizarding world a better place. This could lead to a transformation in Draco's character, and he might even start to have feelings for Hermione, creating a complex and interesting relationship dynamic.
The plot could start with Draco and Hermione realizing their mutual attraction despite their initial animosity. They might secretly plan their elopement to avoid the scrutiny and opposition from their friends and families. Maybe they find a magical place, like an ancient forest where they exchange their vows in a private ceremony.
A possible plot could be that Hermione is getting ready for a big wizarding event and her bra has some sort of magical enchantment on it. Draco accidentally discovers this when he's snooping around (he's still a bit of a troublemaker in this scenario). This discovery leads to a series of events where they have to work together to figure out who enchanted the bra and why. It could be part of a larger plot to embarrass Hermione or to gain some sort of magical advantage.
One possible plot could be that their daughter is a young witch growing up in a world that still has remnants of the old wizarding world rivalries. She could struggle with being the daughter of two former enemies, facing prejudice from some in the wizarding community. She might have extraordinary magical abilities that draw both positive and negative attention, and she has to learn to navigate her own identity while also trying to bridge the gap between the Gryffindor and Slytherin legacies her parents represent.
One possible plot could be that during a potions class, Draco and Hermione accidentally mix the wrong ingredients. This could lead to a magical reaction that causes them to swap personalities. Hermione might start acting like Draco, being more aloof and sarcastic, while Draco could become more studious and rule - abiding like Hermione. They then have to figure out how to reverse the effect while also dealing with the chaos it causes in Hogwarts.
In the fanfiction, perhaps the Ministry of Magic has some concerns about Hermione and Draco adopting Teddy. Since Teddy is the son of Remus Lupin and Nymphadora Tonks, and with his werewolf heritage, they might have to go through a lot of red tape. Hermione, being the brilliant witch she is, would use her knowledge of the law to fight for their right to adopt Teddy. Draco, on the other hand, would use his family's influence and wealth in a more positive way this time. Teddy would start to see them as his real parents, and they would have to deal with the challenges of raising a magical child who has unique abilities and needs.
The plot could involve Teddy facing some sort of danger or mystery that only Hermione and Draco's combined skills can solve. For example, there might be a dark magic threat related to Teddy's family history. Hermione's research skills and Draco's knowledge of the wizarding elite could be crucial in uncovering the truth.
Perhaps it's a time - travel fanfiction. Hermione, using her time - turner for some reason, goes back in time and meets a different Draco. This Draco might be less influenced by his family's pure - blood mania. They start to have feelings for each other, and the kiss is a symbol of their new - found love that defies the normal course of the Harry Potter story. It could also involve Hermione trying to change the future by influencing Draco in the past.
One possible plot could be that they run away to escape the ongoing wizarding war. They find a secluded place, perhaps a hidden cottage in the Forbidden Forest. There, they start to understand each other better without the influence of their respective houses' prejudices. They might discover new magic together and form a bond that is deeper than friendship.
One possible plot twist could be that the tie - switching is part of a magical prank gone wrong. Maybe Hermione and Draco accidentally swap more than just their ties in a spell - mishap. This could lead to them experiencing each other's daily problems at Hogwarts. For example, Draco might have to deal with Hermione's heavy class schedule and the pressure from her friends to always be the top student, while Hermione has to face the Slytherin's snide remarks towards her as she now looks like one of them.
One possible plot reason could be a misunderstanding. Maybe Draco thinks Hermione has some information that she's not sharing and he ties her up to force her to talk. In some fanfictions, it could be part of a game or a dare within the magical world they inhabit. Another reason might be that Draco is being influenced by some dark magic or a curse that makes him act out of character and tie Hermione up.