They would probably meet their old classmates. People like Grover, who was their friend in high school, would surely be there. Maybe some of their old study group members or teammates from school sports teams.
In fanfiction, when Percy and Annabeth meet in high school, they might initially be rivals. Maybe they compete in a school competition like a debate or an academic quiz. Percy, with his street - smart nature, could clash with Annabeth's more studious and methodical approach.
One idea could be that Percy and Annabeth are new students at a high school filled with mythological secrets. They have to hide their demigod status while also dealing with normal high school problems like exams and bullies. Maybe they join the school's swim team and debate club respectively, which could lead to some interesting interactions.
Percy could meet the school bullies. And they might pick on him at first, but then be in for a big surprise when he shows his strength. Also, he might encounter some teachers who suspect there's something different about him. Maybe a science teacher who notices his quick reflexes during an experiment or a history teacher who is amazed by his knowledge of ancient mythology.
There could be a school janitor who is actually an old demigod who retired from the hero business. He could give Percy some valuable advice based on his own experiences. And of course, Percy will surely meet Annabeth's classmates, some of whom could be friendly and some not so much, depending on how they react to the new boy in school.
He might meet normal high school students. There could be the typical jocks, nerds, and popular kids. Maybe he'd encounter a really smart student who is intrigued by Percy's different way of thinking. Or he could meet some mean students who pick on him at first but then learn to respect him.
At first, it could be a bit rocky. Percy might think Annabeth is too uptight, and Annabeth might think Percy is too carefree. But as they spend more time together in the high school environment, perhaps during lunch breaks or in after - school clubs, they start to see the good in each other. For example, Percy might notice how Annabeth always stands up for what's right in class debates, and Annabeth might see Percy's loyalty to his friends.
They could start off on the wrong foot. Maybe Percy accidentally spills something on Annabeth's books. But then, they are paired for a debate in class. They realize that they both have really strong opinions and are quite intelligent. This mutual respect starts the development of their relationship.
One idea could be that they compete in various school competitions like academic decathlon or sports events, always trying to outdo each other. For example, in a science fair, Percy might do a project on underwater ecosystems because of his love for the water, while Annabeth does something related to architecture. Their rivalry makes them both push harder and come up with more creative ideas.
They could be involved in a high school project that turns out to be related to an ancient prophecy. Percy might use his water - controlling abilities in a science experiment in a really cool and unexpected way, and Annabeth would be there to explain the historical context behind it all.