The plot might involve Percy getting lost in Alagaesia. He then has to figure out how to get back home while also getting involved in the local politics and power struggles. Since he's a demigod, he might be seen as a powerful ally or a threat. He could end up using his knowledge of Greek mythology and his own powers to outwit the various factions in Alagaesia.
Well, one possible plot could be Percy using his water - controlling abilities in the world of Alagaesia. Maybe he teams up with the local heroes there and they face some common enemy. For example, a powerful dragon that is threatening both the demigods' world and Alagaesia. He could also introduce new combat styles to the people of Alagaesia based on his training at Camp Half - Blood.
Well, he might get into all sorts of adventures. He could meet the dragons in Alagaesia and try to use his water powers to his advantage against them. Maybe he'd team up with the local heroes there and learn new combat styles.
Eragon could be one of Percy's allies. Eragon has his own set of powers and knowledge of Alagaesia. Percy and Eragon could combine their skills, with Percy's control over water and Eragon's magic and sword - fighting abilities. They could also share their different cultural knowledge, Percy from the world of Greek mythology and Eragon from the world of Alagaesia.
It could be an ancient and powerful dragon that has been awakened by the arrival of Percy in Alagaesia. The dragon might see Percy as a threat to its rule or territory and decides to go after him. This dragon could also have some special abilities that make it difficult for Percy to defeat, like being able to nullify his water powers for a short time.
He would probably meet Eragon. Eragon is a key figure in Alagaesia, and their encounter would be full of surprises as they come from different worlds with different powers.
A great plot could be Percy being sent on a top - secret mission by the army. This mission could be related to some ancient artifact that has military applications but also ties to his demigod world. Along the way, he meets other demigods who are also in the military for various reasons. Together, they have to overcome not only military enemies but also mythical creatures that are after the same artifact.
Well, the plot might start with Percy being sent on a special mission by the gods. They need someone with his quick reflexes and sharp eyesight to be a sniper. Along the way, he has to deal with the moral implications of taking lives from a distance. He might also face challenges in terms of getting the right equipment and training. His friends could be initially skeptical of this new role for him, but as they see him succeed in various battles, they come to accept and rely on his sniper skills.
One possible plot could be Percy using his bike to travel across the country to find and protect other demigods. He could encounter various monsters along the way and use his biker skills, like sharp turns and high - speed maneuvers, to evade them.
One possible plot could be that a powerful enemy, let's say a dark sorcerer, has found a way to use the powers of the Greek gods against the supernatural beings in the Mikaelson universe. Percy Jackson is sent to investigate and ends up getting caught in the middle of the Mikaelson family drama. He has to use his skills as a demigod and his knowledge of Greek mythology to help the Mikaelsons defeat this new threat while also trying to keep his own identity and mission a secret from some of the more untrustworthy members of the family.
Maybe Percy Jackson somehow gets transported to the world of Stranger Things and has to fight the Demogorgon. He could use his water - controlling powers to try and defeat it, like dousing it with a powerful stream of water.