Well, perhaps Loki has tricked the Avengers into believing Percy is working for him. So, they capture Percy. Percy then has to convince them that he's on the side of good and that Loki is just playing them. He might show them his quests and how he's been fighting monsters all this time to prove his innocence.
One possible plot could be that the Avengers mistake Percy for a threat. Maybe they see his powers with water and think he's some kind of new, unknown enemy. They capture him to figure out what he is. Percy, of course, would be confused and probably a bit angry at being wrongly accused.
In this fanfiction, it could be that the Avengers are on a mission to stop any potential super - powered individuals who could cause chaos. Percy's powers are a bit unregulated in their eyes. They capture him to try and train him or at least get him to be more in control. Percy, being the stubborn hero he is, doesn't take kindly to being captured and tries to escape while also trying to make them understand his world.
One possible plot could be that the gods in the Percy Jackson universe sense a great threat from another dimension (the Marvel universe). Percy and his friends are sent to team up with the Avengers. Percy's water powers could be useful in fighting villains like Electro. Annabeth's strategic mind would assist in planning battles against foes like Loki. They all have to learn to work together, with Percy and the Avengers initially having some clashes due to their different ways of handling things.
One possible plot could be that in a world where the gods of Percy Jackson and the Avengers co - exist, Percy is somehow tricked or forced to banish the Avengers. Maybe there's a power struggle among the gods and they see the Avengers as a threat to their power, so they use Percy, who has a strong connection to the divine world, to get rid of them. Percy might be conflicted as he may admire the Avengers' heroism but has to follow the gods' orders.
One possible plot could be that the Greek gods, noticing the powerful threats the Avengers face, send Percy Jackson and his friends to help. Percy could use his water powers to assist in putting out fires during a battle like the one in New York. Meanwhile, Thor could be intrigued by Percy's connection to Poseidon and they could exchange stories about their godly fathers.
Percy has his speed and agility. In the fanfiction, he might be able to use his demigod reflexes to dodge all of the Avengers' attacks. He could then quickly move in for a counter - attack. Also, his sword, Riptide, is a powerful weapon. It can cut through almost anything. He could use it to cut through the Avengers' weapons or their defenses if he gets close enough.
Well, one possible plot could be that the gods in the Percy Jackson universe notice some strange energy disruptions caused by the Infinity Stones in the Avengers' world. Percy and his friends are sent to investigate. They meet the Avengers and at first there are misunderstandings, like the Avengers thinking Percy's powers are from some new form of alien technology. But then they realize they need to work together to stop a common enemy, perhaps a new powerful being that is drawn to the combined power of the demigods and the Infinity Stones.
One possible plot could be that the Avengers are facing a powerful new threat that has some connection to the Greek mythology world. Percy Jackson and his friends are called in to help. Maybe it's a villain who has the power to control both technology like the Avengers are used to dealing with and also the elements of Greek magic. They would have to combine their skills, with Percy using his water - controlling abilities and the Avengers using their high - tech weapons and superpowers to defeat the villain.
One way could be to have Percy Jackson's powers of being a demigod interact with the superpowers of the Avengers. For example, his ability to control water could be used in a joint mission with Thor's lightning powers. Maybe they are facing a common enemy that can only be defeated by combining their unique skills.
Maybe the Avengers are under a curse that is slowly draining their powers. Percy, being a demigod, has some knowledge of curses. He hears about the Avengers' plight and decides to help. He embarks on a journey to find the source of the curse, facing many challenges along the way. Once he finds it, he uses his powers and the help of the Avengers (even with their weakened state) to break the curse and save them.
One possible plot could be that the Avengers mistake Percy Jackson for a dangerous threat. Maybe they've been given false information about his powers being uncontrollable. So, they decide to kidnap him to keep the world safe. But once they have him, they start to realize that he's not what they thought. Percy, being a hero in his own right, tries to convince them that he's on the side of good.
Well, Thor might start by explaining the basic concept of Percy Jackson. He could talk about how Percy is a demigod, the son of Poseidon. The Avengers might be really intrigued. Maybe Tony Stark would make some smart - aleck comments about the magic in the Percy Jackson world compared to their technology. And Steve Rogers would probably be more interested in the hero's journey that Percy undertakes, seeing some similarities to his own experiences.