One interesting plot could be Percy using his water powers in a new way due to his connection to Apollo. Maybe he can heal with water in a more effective way. Another plot could involve Percy and Apollo's other siblings having to team up to fight a new, powerful enemy that threatens the gods and demigods alike. For example, a primordial being awakening.
A possible plot could revolve around Percy's identity crisis. Now that he's considered Apollo's brother, he might struggle with how this new status affects his relationships with his old friends at Camp Half - Blood. He could also face challenges from other demigods who are jealous or suspicious of his new connection. Meanwhile, an ancient curse related to Apollo's family starts to surface, and Percy has to figure out how to break it before it causes chaos.
One possible plot could be Percy getting a special power from Apollo's blessing. For example, he might gain the ability to heal faster, which would be really useful in his battles. He could use this new power to save his friends in a dangerous situation, like when they are facing a powerful monster and his friends are severely injured.
One interesting 'Percy Jackson and Apollo fanfiction' story could be about Apollo teaching Percy some new musical skills related to his powers. Since Apollo is the god of music and Percy has his own unique abilities, their interaction in this aspect can be really fascinating.
One interesting Percy Jackson Apollo fanfiction could be about Apollo having to team up with Percy to face a new and powerful enemy that neither could defeat alone. For example, a primordial being that threatens to destroy Camp Half - Blood. In this fanfiction, Apollo uses his godly powers like his archery skills and prophetic abilities, while Percy uses his water - controlling powers and his combat skills learned from years of fighting monsters.
One interesting story could be about a camper in the Apollo cabin who discovers a hidden power within themselves. Maybe they can control a new aspect of the sun's energy that has never been seen before in the Percy Jackson world. This could lead to all sorts of adventures, like using this power to save the camp from a new and powerful enemy.
Well, a possible storyline is Percy dealing with the expectations of the camps of Apollo and Athena. Since he's the son of both in this fanfiction, he might be pressured to be the best in both areas like archery and battle strategy. He could also go on a quest where he has to use his Apollo - given musical talent to charm a dangerous monster and then use Athena - taught wisdom to outwit another foe.
Another plot could involve the Earthshaker being awakened accidentally. This causes chaos not only on Earth but also in the Underworld. Percy and his companions need to travel to different realms, including the Underworld, to figure out how to put the Earthshaker back to sleep. They encounter different gods and goddesses during their quest, and some might help while others might try to hinder them.
A cool plot could be a time - travel fanfiction. The Minotaur travels back in time to the era when the gods were more actively involved in the mortal world. He could interact with the gods, and Percy has to follow him through time to stop him from causing chaos. This would involve Percy having to deal with different rules and powers in the past, and also understanding the Minotaur's motives for going back in time.
One interesting plot could be where the NPU (assuming it's some new power or entity in the Percy Jackson universe) is a key to unlocking an ancient prophecy that no one knew existed. Percy and his friends have to figure out how to use the NPU to their advantage while also dealing with the usual monsters and gods trying to stop them.
One interesting plot could be the crossover of characters from 'Percy Jackson' and 'The Selection' universes. Maybe Percy finds himself in the world of 'The Selection' and has to deal with the different social and political structures there while still having his demigod powers.
One interesting plot could be Percy having to face an ancient, long - forgotten monster that wasn't in the original series. It adds a new level of danger and adventure.