What are some interesting plot ideas in 'Harry Potter has a twin sister fanfic'?

She could be the key to unlocking some long - forgotten secrets about their parents. Maybe she discovers a hidden diary or a magic object that reveals things about their family's past that even Dumbledore doesn't know. This could put her in danger as there might be dark forces who don't want those secrets to come out. Harry then has to protect her while they figure out what to do with the new - found information.

Maybe the twin sister has a different type of magic than Harry. For example, while Harry is known for his connection to Voldemort and his Parseltongue ability, she could have the power of prophecy. She starts having strange dreams about future events in the wizarding world that are crucial to saving it from new threats, and she has to figure out how to interpret and act on these prophecies.

One interesting plot line could be how the twin's presence affects Harry's relationships at Hogwarts. Maybe the twin has a different personality and befriends characters that Harry doesn't usually interact with much, like some of the Slytherins. This could lead to a whole new set of adventures and alliances within the school.

One idea could be that the twin sister has a special power that Harry doesn't. For example, she can communicate with animals. This would add a new dynamic to the story as she could use this ability to gather information or help in dangerous situations. Another plot could be that the twin sister gets sorted into a different house than Harry at Hogwarts. This would cause some tension and also show different perspectives within the wizarding world. A third idea is that the twin sister discovers a hidden secret about their family that Harry is oblivious to, and she has to figure out how to tell him and what to do about it.

Maybe the twin sister gets sorted into a different house than Harry. This creates an interesting dynamic as they have to navigate their loyalty to their house as well as their bond as twins. She could be in Slytherin, which would cause some tension at first but then they find ways to work together despite the house rivalries.

One idea could be that Harry's little sister has a unique magical ability that no one else in the family has. For example, she might be able to communicate with magical creatures in a way that even Hagrid is impressed by. This could lead to all sorts of adventures where she helps solve problems in the wizarding world using this special skill.

One interesting plotline could be how the twin sister helps Harry deal with the challenges at Hogwarts in a different way than his friends. Maybe she has a unique magical ability that aids them in fighting the dark forces.

A cool plot could be that the twins cross over into a dimension where they are sorted into different houses. Fred in Slytherin and George in Gryffindor. This would create an interesting dynamic as they deal with the different values and expectations of their new houses while still maintaining their close bond. They could also have to face the prejudice and misunderstandings from their housemates due to their 'unusual' sorting.

One idea could be that Naruto and his twin sister have a special bond that allows them to share chakra in unique ways. For example, when Naruto is in a tough battle and running low on chakra, his sister can transfer some of hers to him, even from a distance. Another plot could revolve around them both having a secret mission that only they are trusted with by the Hokage. This mission could be related to an ancient prophecy that involves the siblings.

One interesting plot twist could be that the forgotten twin has a different magical ability than Harry. For example, while Harry is good at Defense Against the Dark Arts, the twin might be a natural at Potions or Charms. This could lead to a situation where the twin is initially seen as an outcast in Hogwarts because their skills don't match the typical Gryffindor traits. Another plot twist could be that the forgotten twin was actually hidden away by a powerful dark wizard who planned to use the twin's power for their own evil purposes. This would put the twin in a difficult position when they discover their true past and have to decide whether to side with the forces of good or be influenced by the dark wizard's plans.