A cool plot could be that on Percy's birthday, the gods decide to grant him a special wish. But there's a catch - he has to complete a mini - quest first. So Percy, along with his closest friends, embarks on this quest that takes them to a mysterious island. On the island, they face various challenges, like fighting off strange monsters. When they finally succeed, Percy gets his wish, which could be something like ensuring the safety of all his friends at Camp Half - Blood forever.
Another plot could be that Percy and Clarisse are trapped in a parallel dimension. In this dimension, the rules of Camp Half - Blood are different, and they are considered outcasts. They have to find a way to get back to their own dimension. Along the way, they meet strange versions of their friends and enemies. They rely on each other's unique skills. Percy uses his wits to figure out the strange magic at work in this dimension, while Clarisse uses her courage to face the dangerous creatures. As they work together, they grow closer and finally find a way back home, with a much - improved relationship.
Well, the OC could be a daughter of a minor god. Percy first meets her when she's in trouble in the mortal world. He saves her and brings her to Camp Half - Blood. As she tries to fit in, Percy helps her a lot. Their love story could develop as they discover secrets about her parentage together and find out that they are fated to be together in some way, like they are part of an old prophecy.
One possible plot could be that the OC is a new camper at Camp Half - Blood. They meet a demigod from a different cabin during a training session. The two initially clash due to different fighting styles, but as they are forced to team up on a quest, they start to see each other's strengths and fall in love. For example, the OC might be a child of Aphrodite who is more into charm and persuasion, while the other demigod is a son of Ares, focused on brute force.
For a Danny Phantom birthday fanfiction, it could be that Danny's birthday coincides with a rare ghostly phenomenon that only occurs once every century. Ghosts from all over the world are drawn to Amity Park. Some are friendly and want to celebrate with Danny, but others are there to cause chaos. Danny must navigate through this strange day, dealing with both the well - meaning and the malicious ghosts, while also trying to have a normal birthday celebration with his human friends and family.
A great plot could be that on Wordgirl's birthday, all the villains in the city decide to give her a day off from fighting them. Instead, they plan a big surprise party for her, but they keep arguing about how to do it right. In the end, they all work together and create a really fun and unique party that Wordgirl never expected, which also helps to build a better relationship between her and the villains.
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.