Well, perhaps Percy could find himself in a dimension where the laws of physics are completely different. He might have to learn new ways to use his powers. For example, if water behaves strangely there, like it's solid in some areas and gas in others, he'd have to adapt quickly.
Maybe it's a corrupted version of one of the gods from Percy's world who has gained even more power in this new dimension. They could be trying to spread chaos and destruction, and Percy has to stop them. This antagonist would know Percy's weaknesses from their time in the original world, which would make the conflict more intense.
Maybe Amy discovers a magical portal in her attic that leads to another dimension. In that dimension, the laws of physics are different, and she has to adapt quickly to survive. There could be strange creatures she befriends or battles against.
Well, perhaps Natsu could find himself in a dimension where magic works completely differently. He might have to learn new ways to use his fire magic or even discover new types of magic altogether. Maybe he meets alternate versions of his friends who have different personalities due to the different environment of that dimension.
In this fanfiction, Percy might encounter different versions of his friends. For example, Annabeth could be a powerful sorceress instead of a strategist. He could also face new and strange monsters that are unique to that universe.
In this fanfiction, it might be that Percy goes missing because he is on a self - imposed mission. He could be trying to protect his friends from a danger he discovers, and he doesn't want to involve them, so he disappears without a trace. He might be in a far - off land, facing challenges all alone.
Well, perhaps Percy could be a new student at Hogwarts. He might face challenges like making friends in a new and magical environment. Maybe he gets sorted into a house and has to learn to fit in with his new housemates. He could also discover some hidden secrets about Hogwarts that are not known to many.
Maybe Percy will face new challenges in college like dealing with difficult classes. He could also meet new friends or enemies. And perhaps he'll discover new powers or secrets related to his special nature.
One possible plot twist could be that in the other dimension, Naruto finds out that all his friends have different personalities. For example, Sasuke could be a peaceful scholar instead of a brooding avenger. Another twist might be that the chakra system works completely differently in this new dimension. Maybe instead of using hand signs, they use some kind of mental power to perform jutsus. Also, Naruto could discover that the Akatsuki in this dimension are actually the good guys, fighting against an evil ninja clan that wants to take over the world.
He might encounter new and strange creatures. In many fanfictions, Percy could meet unique magical beings that don't exist in his own world. For example, he could come across sentient plants that can communicate or floating islands with their own mini - ecosystems.
Well, it could be about Sakura exploring a magical new world filled with strange creatures. Maybe she has to find a way back home while making new friends along the way.