The plot might involve Percy discovering some hidden secrets about Zoe's past. Since he's her brother in this fanfiction, he feels responsible for uncovering the truth. It could lead them on a journey to a forgotten place, like an ancient temple. Along the way, they face various challenges. For example, they might encounter traps set by an old enemy of Zoe's family. Percy uses his quick thinking and Zoe her knowledge of ancient lore to get through these obstacles.
Well, one possible plot could be Percy and Zoe having to team up against a common enemy. Maybe a new powerful monster emerges that neither of them can defeat alone. So, they have to put aside their differences (if any) and combine their skills. Percy with his water powers and Zoe's archery skills would make a great team. They could start out not trusting each other much, but as the story progresses, they learn to rely on one another and form a strong bond.
One possible plot is that Percy and Zoe are on a quest related to their family. Since they are siblings in this fanfiction, they could be looking for something that was lost by their ancestors. Along the way, they meet various characters who either help or hinder them, and they learn more about each other and their family's past.
The plot could be centered around a prophecy that involves both Percy and Zoe. They are forced to team up despite their initial differences. For example, Percy is more impulsive and Zoe is more reserved. As they journey to fulfill the prophecy, they encounter mythical creatures and ancient magic that test their limits.
Well, it could be about Percy discovering he has this unexpected connection to Ares. And then he has to deal with the reactions of his friends like Annabeth. Some of them might be distrustful of this new relation. Percy would then try to find out more about his connection to Ares through exploring old prophecies and ancient sites, all while trying to keep his regular demigod duties in check.
Well, one possible plot could be Percy discovering he's Zeus' brother in a very unexpected way. Maybe through some ancient prophecy that was long forgotten. He'd then have to deal with the power struggles within the Olympian family, as well as his own identity crisis. Another aspect could be his relationships with other demigods changing, as being related to Zeus is a huge deal.
Well, one possible plot could be Percy having to hide his relation to Kronos while still fighting against the Titans. He might struggle with the internal conflict of having a connection to such an evil entity as Kronos while trying to protect his friends at Camp Half - Blood.
One possible plot could be Percy discovering his connection to Achilles while on a new quest. Maybe he has to face a powerful enemy that only his newfound link to Achilles can help him defeat. For example, he might gain some of Achilles' combat skills or invulnerability in certain situations.
The fanfiction could revolve around the origin of Percy's brother's space powers. It might be that he was experimented on by some dark force in the past which gave him these powers. Percy and his friends then have to find a way to reverse or control these powers before they go out of hand. The brother could accidentally be creating black holes or warping the demigod world with his unstable powers, and Percy has to use his own skills and the help of the gods to save the day.
At first, their relationship could be a bit rocky. Zoe might be hesitant to accept Percy as her brother. After all, she has her own way of life and Percy is quite different. But as they face challenges together, like fighting off some mythical creatures, they start to respect each other. Percy would see Zoe's courage and Zoe would see Percy's determination.
One possible plot could be Percy and Zoe facing numerous dangerous monsters in Tartarus. They might have to rely on each other's unique abilities. For example, Percy's control over water could help them cross certain deadly rivers while Zoe's hunting skills could be used to fend off the approaching beasts.
If Percy saves Zoe, it would likely have a significant impact. Maybe it unlocks hidden powers for Percy or makes Zoe more dependent on him. There are so many possibilities for how this could unfold.