The plot could be that Percy's girlfriend is a time - traveler. She comes from the future and warns Percy about a great danger that is going to befall his world. Percy is initially skeptical but soon realizes she is telling the truth. They then embark on a journey to stop this danger. Along the way, their relationship deepens as they rely on each other's strengths. Percy uses his combat skills and the girlfriend uses her knowledge of the future to outwit their enemies.
His secret girlfriend could be in a difficult situation herself. Maybe she's a demigod with a dangerous family or past. Percy is trying to help her while keeping their relationship a secret. This could involve them sneaking around to meet, sharing secret glances in public, and having to communicate in coded ways. It would create a really interesting and suspenseful plot.
One possible plot could be that Percy's son is starting at Hogwarts and is having a hard time living up to his father's reputation. He might struggle with the expectations placed on him due to his family name. Maybe he doesn't have the same academic prowess as Percy did at his age and has to find his own way to shine in the wizarding world.
Perhaps the sister gets kidnapped by an enemy of Percy's. Percy then has to embark on a dangerous quest to rescue her. Along the way, he discovers more about his sister's true nature and their family's past that was previously unknown to him. This could involve meeting old friends and making new allies.
One possible plot could be that Ash and his girlfriend go on a Pokémon journey together. They encounter rare Pokémon and have to work as a team to catch them. Along the way, they face challenges from rival trainers who are jealous of their relationship and try to break them apart. But through their love and trust in each other, they overcome all difficulties.
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.
One possibility could be that Percy has been leading a double life. Maybe he had a relationship in the past that he kept hidden, and now the existence of the child is coming to light. The story could explore how he copes with this new reality and how it affects his relationships with his friends and family.
In a Percy Jackson has a Omnitrix fanfiction, the plot could involve Percy being sent on a special mission by Chiron. During this mission, he stumbles upon the Omnitrix. He soon discovers that the Omnitrix has some sort of connection to the Greek gods. As he uses it to transform into various alien forms, he finds that each form has a unique ability that can either help or hinder him in his quest. For example, one form might be able to swim super fast in the ocean, which is great for underwater battles, but another form might be weak against fire, which could be a problem when facing a fire - breathing monster. Along the way, he has to learn to balance his use of the Omnitrix with his own demigod skills and knowledge of Greek mythology to succeed in his mission.
Well, it could be about Percy being in a very stressful situation like facing a powerful enemy he's not sure he can defeat. This causes him to have a panic attack. Maybe he starts hyperventilating and his friends have to come to his rescue and calm him down.
Well, it could be about Percy using his siren - like voice to charm people in the story. Maybe he uses it to get out of tricky situations or to help his friends. For example, he might use it to calm down an angry monster and avoid a fight.
The plot could involve Percy waking up one day and finding a tail instead of his legs. At first, he's confused and a bit scared. But then he realizes it gives him some new abilities, like super - fast swimming. He could then go on a quest where his tail is both an advantage and a hindrance. For example, it might be hard to move on land, but in water, he can out - swim any monster.