What are some interesting plot ideas for Percy Jackson's little sister in fanfiction?

One idea could be that his little sister discovers a new, hidden power within herself while on a quest with Percy. Maybe she can communicate with mythical creatures in a unique way that helps them solve a mystery.

Another plot could involve the twin sister being cursed. This curse could be related to her connection with the sea as well. For example, every time she uses her powers related to the sea, she experiences a great deal of pain. Percy then has to find a way to break the curse. In the process, they discover an ancient prophecy that not only involves Percy but also depends on his sister's role in fulfilling it.

One idea could be that Percy discovers he has a Roman sister who has unique powers. Maybe she can control the winds in a way that's different from the known demigods. Their relationship could be strained at first as they come from different worlds, but as they face challenges together, they grow closer. For example, they might have to team up against a powerful monster that is targeting both Camp Half - Blood and Camp Jupiter.

Well, perhaps they discover a hidden prophecy that involves both of them. They then must travel to different realms, such as the Underworld and Olympus, to seek answers. Along the journey, they learn more about their godly heritage and how to use their powers in harmony. They might also encounter some old enemies of their godly parents who are out for revenge.

One idea could be that Percy's baby sister discovers she has a unique power that even Percy doesn't have. For example, she might be able to communicate with the spirits of the ancient Greek heroes in a way that gives her special knowledge. Another plot could be that she gets kidnapped by a new enemy who wants to use her to get to Percy. Percy then has to go on a dangerous quest to rescue her, facing all kinds of mythical creatures along the way. A third idea is that she is actually a reincarnation of an important figure from Greek mythology, and as she grows up, she starts to remember her past life and the secrets it holds, which causes a stir in the demigod world.

Well, a great plot could be that Percy's mortal sister is being targeted by a minor villain from the demigod realm. This villain thinks that by getting to her, they can get to Percy. So, Percy has to protect her while also trying to keep her in the dark about his world as much as possible. But as time goes on, she starts to piece things together. She could also make friends with some of the less powerful demigods who are more in touch with the mortal world, and they help her understand and deal with the situation.

One idea could be that they discover their relation during a magical crisis. Maybe a dark force is threatening both the wizarding world and the demigod world, and their combined powers as siblings help save the day. For example, Hermione's magic and knowledge of spells combined with Percy's control over water and his demigod strength.

One plot idea could be that Lemon has a special power that no one else in the demigod world has, and Percy has to protect her from the gods who want to use or destroy her because of it.

One plot idea could be Percy having to team up with Hera to rescue a group of demigods who have been captured by an ancient monster. Hera, despite her usual aloofness, realizes she needs Percy's unique skills.

A great plot could be that the children are sent on a quest to a new, mysterious location that was previously unknown in the Percy Jackson universe. They might have to deal with strange new monsters and make allies among the local mythical beings. For example, they could end up in a hidden valley where the spirits of nature are at war, and they have to figure out how to restore balance. This would involve them using their powers in new and creative ways, just like their parents did in the original series.