One idea could be Percy and Thalia teaming up against a powerful new enemy that neither could face alone. Their combined powers and sibling bond make them a formidable force.
Maybe a story where Percy discovers he's Thalia's brother and they have to go on a journey to find out more about their family's past. Along the way, they face various challenges that test their relationship and their abilities.
One idea could be that Thalia's twin brother has some hidden power that is the key to saving Percy and his friends in a big battle. Maybe he can communicate with a special type of mythical creature that others can't. Another plot could involve the twin brother having a prophecy related to Percy, and they have to team up to fulfill it, despite initial mistrust.
A plot could revolve around them having to protect a young demigod who is being hunted by a powerful enemy. Percy and Thalia have different approaches to protection, and they might argue at first. But as they face more danger, they realize that they need to work together. Their sibling relationship would grow stronger as they defend the young demigod.
One idea could be that they discover a long - lost family heirloom together. They go on a quest to figure out its significance and along the way, they face various monsters and challenges. It could strengthen their bond as siblings.
Perhaps a fanfiction where Percy and Thalia are transported to an alternate dimension. In this new world, they have to figure out how to get back while also dealing with different versions of their friends and enemies. Thalia might have to face an alternate version of herself who has turned evil, and Percy could be the one to help her see the light again. It would be full of action, drama, and self - discovery.
One idea could be Percy and Thalia teaming up to protect a group of young demigods who are being hunted by a new and powerful monster. They could use their combined skills, Percy's water powers and Thalia's electric ones, to fend off the attacks.
One idea could be that Thalia and Percy are on a dangerous quest together. In the middle of it, they find a mysterious lemon - themed garden that has magical properties. The lemon trees might have fruits that can heal wounds or give them special powers. They have to protect this garden from monsters while also exploring their feelings for each other.
Maybe they are all transported to an alternate dimension where the rules of their world are different. Percy has to figure out how to use his powers without water, Thalia discovers new aspects of her lightning, and Nico has to deal with different types of underworld creatures. They must find a way to get back home while also helping the people in this new dimension.
One idea could be that they discover their twin bond gives them unique powers. For example, they can combine their skills in combat, like Percy's water control and Thalia's lightning, to defeat a powerful enemy. Another plot could involve them exploring their family history together, finding out secrets about their parents that change their view of themselves. Maybe they meet a relative who knew about their twin relationship all along but was sworn to secrecy.
One plot idea could be Percy and Thalia going on a quest together to find a lost artifact that has the power to save their camp from a new threat. Another could be them getting into an argument over how to handle a new demigod at camp, which tests their friendship but ultimately makes it stronger. Maybe they could also travel to a different realm together where they have to rely on each other completely to survive and get back home.
Maybe a plot where Dark Percy has some sort of power that Thalia needs to save someone she loves. Thalia has to convince Percy to use his powers for good in this case, and in the process, they develop a complex relationship. Percy is conflicted between his dark side and the pull he feels towards Thalia's cause.