A more complex plot could be a love triangle situation where Arya, Percy, and one of Percy's friends from his world are all involved. This would create a lot of drama and tension as they try to figure out their feelings while also dealing with the various threats and challenges in their worlds.
One interesting plot could be Percy having to team up with Athena in a quest that involves outsmarting a powerful enemy. Since Athena is the goddess of wisdom, she uses her intelligence to create strategies, and Percy has to follow them, which is a big change from his usual more impulsive adventures.
Another plot might involve Percy being accidentally transported to a time when the male gods were still young. He has to figure out how to get back to his own time while also getting involved in the gods' early adventures. He could end up changing some small things in the past that have unexpected consequences in his present time.
One interesting plot could be Percy having to deal with new mythological threats while trying to balance his college studies. For example, a group of rogue satyrs causing chaos on campus. Another plot might involve Percy and his friends forming a secret society in college to protect the mortal world from hidden magical dangers. And sometimes, there are plots where Percy has a love interest who is also involved in the world of Greek mythology and they face challenges together in the college setting.
One interesting plot could be Percy and his friends going on a quest in a new, unknown realm. Maybe a place that's not part of the regular Greek mythology but still related in some way.
A great plot might involve Percy and Calypso going on a quest to save a group of demigods. Along the way, they face various monsters and challenges, and their relationship deepens as they rely on each other. They could also discover some hidden secrets about the gods during this quest.
One interesting plot could be Phoebe joining Percy on a quest. Maybe she has some unique powers that help them overcome the challenges they face, like being able to communicate with certain mythical creatures that Percy can't. This could add a new dynamic to the typical Percy Jackson quest.
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.