Well, one possibility could be that Percy has been on some sort of adventure and during that time, he discovers a child in need. He decides to take the child under his wing and brings the child back to his world. Then, he has to deal with the reactions of his friends and family, who are both surprised and a bit worried about this new addition.
The child could be an orphan from a far - off land that Percy visited. Maybe Percy found the child alone and starving, and felt responsible for the child's well - being, so he brought the child back.
One possible plot could be that Naruto has been on a long and secret mission. During this time, he met someone and had a child. Now he returns to the village with the child, and the villagers are both shocked and curious. His friends, like Sasuke, might be initially skeptical but then come to accept the new situation. The child could also have some unique powers inherited from Naruto, which could lead to various adventures as they try to figure out how to control and develop these powers.
One possible plot could be that Percy returns with new powers. Maybe he was resurrected by some ancient magic or a powerful deity who has a plan for him. He then has to deal with the shock and awe of his friends and also face new enemies who are either threatened by his return or want to use his newfound powers for their own gain.
Well, it could involve Percy coming back with new powers. Maybe he's more in tune with the underworld's magic. He might have made some sort of deal in Tartarus and now has to deal with the consequences in the mortal world.
One possibility could be that Percy returns with new powers. Maybe he has some connection to the Underworld now that he's come back from the dead. He might be able to control the dead or has some knowledge about the afterlife that he uses to help his friends in battles against new and more powerful enemies.
Well, he might disappear because of a powerful curse from an ancient enemy. Maybe he gets trapped in a different dimension. When he returns, he could have new powers or knowledge. For example, he might have learned some secret magic from the other dimension that helps him defeat a new threat in the Percy Jackson world.
Well, perhaps Percy comes back to find his old friends have changed a great deal. Maybe some have new powers or positions in their world. He could be faced with a new threat that only he can help to defeat because of his unique past experiences.
Maybe the plot would revolve around the relationship between Percy and the goddess. It could show how they met, fell in love, and decided to have a child. Then it might explore how the other gods and goddesses react to this union and the birth of the child.
The plot might involve Percy having to protect the child from the various horrors of Tartarus. Maybe he has to fight off monsters while trying to find a way to get the child out safely.
One possible plot could be that Percy, as a child, has to navigate his newfound smallness while still having the memories of his older self. He might struggle to convince his friends that he is actually Percy, and they initially think it's some sort of trick. Then, he could use his knowledge from his older self to help them in a new and unexpected way, like solving a mystery that the younger versions of them couldn't figure out on their own.